cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

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A026495 a(n) = least positive integer > a(n-1) and not a(i)^2 + a(j)^2 + a(k)^2 for 1<=i

Original entry on oeis.org

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Offset: 1

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Comments

Starts to differ from A004440 at a(102). - Robert Israel, Jul 22 2025

Crossrefs

Cf. A004440. [From R. J. Mathar, Oct 23 2008]

Programs

  • PARI
    {m=70; z=300; a=[]; a2=Set([]); a3=Set([]); s=1; for(n=1, m, p=s; while(setsearch(a3, p, 0), p++); if(p>z, break); new=vector(#a2); for(k=1, #a2, q=eval(a2[k])+p^2; if(q<=z, new[k]=q)); a3=setunion(a3, Set(new)); new=vector(#a); for(k=1, #a, q=a[k]^2+p^2; if(q<=z, new[k]=q)); a2=setunion(a2, setminus(Set(new), Set(0))); a=concat(a, p); s=p+1; print1(p, ","))} /* Klaus Brockhaus, Jul 03 2008 */

Extensions

Extended by Klaus Brockhaus, Jul 03 2008
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