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.

A354990 Ordinal transform of A344005, where A344005(n) is the smallest positive integer m such that n divides m*(m+1).

Original entry on oeis.org

1, 2, 1, 1, 1, 2, 1, 1, 1, 2, 1, 2, 1, 2, 1, 1, 1, 2, 1, 3, 3, 2, 1, 3, 1, 2, 1, 2, 1, 2, 1, 1, 1, 2, 1, 4, 1, 2, 3, 2, 1, 4, 1, 2, 1, 2, 1, 3, 1, 2, 1, 4, 1, 2, 3, 3, 3, 2, 1, 4, 1, 2, 1, 1, 1, 3, 1, 3, 1, 2, 1, 5, 1, 2, 3, 1, 1, 5, 1, 5, 1, 2, 1, 1, 1, 2, 1, 1, 1, 2, 1, 2, 3, 2, 2, 2, 1, 2, 1, 4, 1, 2, 1, 1, 3
Offset: 1

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Author

Antti Karttunen, Jun 17 2022

Keywords

Comments

Number of values of k, 1 <= k <= n, with A344005(k) = A344005(n).

Crossrefs

Cf. also A344770, A345934.

Programs

  • PARI
    up_to = 65537;
    ordinal_transform(invec) = { my(om = Map(), outvec = vector(length(invec)), pt); for(i=1, length(invec), if(mapisdefined(om,invec[i]), pt = mapget(om, invec[i]), pt = 0); outvec[i] = (1+pt); mapput(om,invec[i],(1+pt))); outvec; };
    A344005(n) = for(m=1, oo, if((m*(m+1))%n==0, return(m))); \\ From A344005
    v354990 = ordinal_transform(vector(up_to,n,A344005(n)));
    A354990(n) = v354990[n];

Formula

a(n) >= A354991(n).