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Start all of your commands with a comma

https://rhodesmill.org/brandon/2009/commands-with-comma/
102•theblazehen•2d ago•23 comments

OpenCiv3: Open-source, cross-platform reimagining of Civilization III

https://openciv3.org/
654•klaussilveira•13h ago•190 comments

The Waymo World Model

https://waymo.com/blog/2026/02/the-waymo-world-model-a-new-frontier-for-autonomous-driving-simula...
944•xnx•19h ago•550 comments

How we made geo joins 400× faster with H3 indexes

https://floedb.ai/blog/how-we-made-geo-joins-400-faster-with-h3-indexes
119•matheusalmeida•2d ago•29 comments

What Is Ruliology?

https://writings.stephenwolfram.com/2026/01/what-is-ruliology/
38•helloplanets•4d ago•38 comments

Unseen Footage of Atari Battlezone Arcade Cabinet Production

https://arcadeblogger.com/2026/02/02/unseen-footage-of-atari-battlezone-cabinet-production/
48•videotopia•4d ago•1 comments

Show HN: Look Ma, No Linux: Shell, App Installer, Vi, Cc on ESP32-S3 / BreezyBox

https://github.com/valdanylchuk/breezydemo
228•isitcontent•14h ago•25 comments

Jeffrey Snover: "Welcome to the Room"

https://www.jsnover.com/blog/2026/02/01/welcome-to-the-room/
14•kaonwarb•3d ago•18 comments

Monty: A minimal, secure Python interpreter written in Rust for use by AI

https://github.com/pydantic/monty
219•dmpetrov•14h ago•114 comments

Show HN: I spent 4 years building a UI design tool with only the features I use

https://vecti.com
329•vecti•16h ago•143 comments

Sheldon Brown's Bicycle Technical Info

https://www.sheldonbrown.com/
378•ostacke•19h ago•94 comments

Hackers (1995) Animated Experience

https://hackers-1995.vercel.app/
487•todsacerdoti•21h ago•241 comments

Microsoft open-sources LiteBox, a security-focused library OS

https://github.com/microsoft/litebox
359•aktau•20h ago•181 comments

Show HN: If you lose your memory, how to regain access to your computer?

https://eljojo.github.io/rememory/
286•eljojo•16h ago•167 comments

An Update on Heroku

https://www.heroku.com/blog/an-update-on-heroku/
409•lstoll•20h ago•276 comments

Vocal Guide – belt sing without killing yourself

https://jesperordrup.github.io/vocal-guide/
21•jesperordrup•4h ago•12 comments

Dark Alley Mathematics

https://blog.szczepan.org/blog/three-points/
87•quibono•4d ago•21 comments

PC Floppy Copy Protection: Vault Prolok

https://martypc.blogspot.com/2024/09/pc-floppy-copy-protection-vault-prolok.html
59•kmm•5d ago•4 comments

Where did all the starships go?

https://www.datawrapper.de/blog/science-fiction-decline
4•speckx•3d ago•2 comments

Delimited Continuations vs. Lwt for Threads

https://mirageos.org/blog/delimcc-vs-lwt
31•romes•4d ago•3 comments

How to effectively write quality code with AI

https://heidenstedt.org/posts/2026/how-to-effectively-write-quality-code-with-ai/
251•i5heu•16h ago•194 comments

Was Benoit Mandelbrot a hedgehog or a fox?

https://arxiv.org/abs/2602.01122
15•bikenaga•3d ago•3 comments

Introducing the Developer Knowledge API and MCP Server

https://developers.googleblog.com/introducing-the-developer-knowledge-api-and-mcp-server/
56•gfortaine•11h ago•23 comments

I now assume that all ads on Apple news are scams

https://kirkville.com/i-now-assume-that-all-ads-on-apple-news-are-scams/
1062•cdrnsf•23h ago•444 comments

Why I Joined OpenAI

https://www.brendangregg.com/blog/2026-02-07/why-i-joined-openai.html
144•SerCe•9h ago•133 comments

Learning from context is harder than we thought

https://hy.tencent.com/research/100025?langVersion=en
180•limoce•3d ago•97 comments

Understanding Neural Network, Visually

https://visualrambling.space/neural-network/
287•surprisetalk•3d ago•41 comments

I spent 5 years in DevOps – Solutions engineering gave me what I was missing

https://infisical.com/blog/devops-to-solutions-engineering
147•vmatsiiako•18h ago•67 comments

Show HN: R3forth, a ColorForth-inspired language with a tiny VM

https://github.com/phreda4/r3
72•phreda4•13h ago•14 comments

Female Asian Elephant Calf Born at the Smithsonian National Zoo

https://www.si.edu/newsdesk/releases/female-asian-elephant-calf-born-smithsonians-national-zoo-an...
29•gmays•9h ago•12 comments
Open in hackernews

Sequence and first differences together list all positive numbers exactly once

https://oeis.org/A005228
81•andersource•7mo ago

Comments

8organicbits•7mo ago
OEIS is such a wonderful reference. I've had occasions where software I was building needed to compute certain sequences, but I hadn't yet figured out the underlying math. I popped the sequence into OEIS and found the closed form solution. It was a huge productivity boost.
nurettin•7mo ago
For me it was a favorite place to visit every so often. I also really enjoyed mathworld.wolfram.com a few decades ago. (A true shame that he went insane)
volemo•7mo ago
> A true shame that he went insane

Could you elaborate on your reasons for calling Eric Weisstein insane?

Rexxar•7mo ago
He probably intends to call Stephen Wolfram like that. But it's ridiculous to call him insane because he seems a little obsessed by cellular automatons.
nurettin•7mo ago
Weisstein is amazing. Wolfram has the "unified theory of everything" disease. So much so that he sponsored dozens of youtube channels to talk about it.
foodevl•7mo ago
I don't know (and don't need you to elaborate on) exactly what you're referring to in that last sentence, but I suspect you are confusing Eric W. Weisstein with Eric Weisstein.
quietbritishjim•7mo ago
More likely he's confusing the mathworld author with Stephen Wolfram
lutusp•7mo ago
> A true shame that he went insane

I assume you're referring to Stephen Wolfram, not Neil Sloane, but it seems many people would like clarification.

As to Wolfram, assuming this is your focus, nothing undermines one's sanity as reliably as complete success. Not to accept your premise, only to explain it.

HocusLocus•7mo ago
Like 'even and odd' on steroids.
kleiba•7mo ago
Coding exercise: write a function

    boolean isInSequence(n):
that decides whether the given integer is part of that sequence or not. However, pre-storing the sequence and only performing a lookup is not allowed.
rokob•7mo ago
return n >= 0
r0uv3n•7mo ago
2 for example is not in the sequence. Remember that you need the first differences to this sequence to obtain all natural numbers
rokob•7mo ago
Hah oh right duh
vbezhenar•7mo ago
Compute the sequence until you get n or m > n?
haskellshill•7mo ago
How about the following Haskell program?

    rec ((x:xs),p) = (filter (/= p+x) xs,p+x)
    sequ = map snd $ iterate rec ([2..],1)
sequ is an infinite list of terms of the sequence A005228.
sltkr•7mo ago
That just enumerates the entire sequence; I think the challenge is to do it faster than that.

By the way, the use of `filter` makes your implementation unnecessarily slow. (The posted link also contains Haskell code, which uses `delete` from Data.List instead of `filter`, which is only slightly better.)

I'd solve it like this, which generates both sequences in O(n) time, and the mutual recursion is cute:

    a005228 = 1 : zipWith (+) a005228 a030124

    a030124 = go 1 a005228 where
        go x ys
            | x < head ys = x     : go (x + 1) ys
            | otherwise   = x + 1 : go (x + 2) (tail ys)
asboans•7mo ago
I don’t know but I think I could probably implement IsInSequenceOrFirstDifferences(n)
cluckindan•7mo ago
Recursive (n choose 2) is my favorite.

https://oeis.org/A086714

If you think about it, it quantifies emergence of harmonic interference in the superposition of 4 distinct waveforms. If those waveforms happen to have irrational wavelengths (wrt. each other), their combination will never be in the same state twice.

This obviously has implications for pseudorandomness, etc.

OscarCunningham•7mo ago
Is there a sequence where the sequence and all its differences contain each positive integer once?

Something like

    1 3 9   26  66
     2 6  17  40
      4 11  23
       7  12
        5
Oh, here it is: https://oeis.org/A035313
thaumasiotes•7mo ago
> Oh, here it is: https://oeis.org/A035313

That sequence is not known to match what you asked for:

>> Conjecturally, every positive integer occurs in the sequence or one of its n-th differences, which would imply that the sequence and its n-th differences partition the positive integers.

For an intuition of why this might be hard to prove, note that you had to insert 7 into your structure before you inserted 5. In the general case, there might be a long waiting period before you're able to place some particular integer n. It might be infinitely long.

vishnugupta•7mo ago
Can someone please explain this to me? I tried to make sense but couldn’t.
Horffupolde•7mo ago
The sequence union the differences span all integer values.
munchler•7mo ago
The initial sequence is 1, 3, 7, 12, 18, 26, 35, etc. The difference between each term in that sequence produces a second sequence: 2, 4, 5, 6, 8, 9, 10, etc. If you merge those two sequences together in sorted order, you get 1, 2, 3, 4, 5, 6, 7, etc. Each whole number appears in the result exactly once.
vishnugupta•7mo ago
Really good explainer. Thank you!
card_zero•7mo ago
By end of the sequence shown on the page, the contiguous part has only reached 61. After that it's full of gaps: it's hit 1689, but has not yet hit 62. The last three differences shown there are 59, 60, 61. So it will list all integers mainly because the differences are increasing similar to the ordinary number line.
Aardwolf•7mo ago
I wonder why the title of the sequence isn't set to "Hofstadter's sequence" since that seems to be what it's called according to A030124 when it refers back to this one
andersource•7mo ago
Hofstadter introduces several sequences in GEB, [0] may be an interesting submission on its own but I was especially captivated by this self-referencing one. Plus a title including both Hofstadter's sequence and a description is too long for HN and I preferred the descriptive one

[0] https://en.wikipedia.org/wiki/Hofstadter_sequence

Aardwolf•7mo ago
I meant the title as it appears in OEIS, not as it appears on HN :)
andersource•7mo ago
Ah :)

From my (limited) experience the OEIS titles lean strongly to the descriptive side too. But maybe also to avoid ambiguity regarding to which one is it from his sequences?