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.

A344762 "Twisted variant" of A342002: a(n) = A342001(A328627(n)) = A342002(A328626(n)).

Original entry on oeis.org

0, 1, 1, 7, 2, 5, 1, 7, 14, 47, 16, 43, 2, 9, 8, 59, 22, 31, 3, 11, 17, 41, 13, 49, 4, 13, 11, 53, 19, 37, 1, 9, 10, 55, 17, 41, 27, 89, 128, 479, 187, 361, 39, 113, 116, 503, 199, 337, 31, 97, 164, 407, 151, 433, 43, 121, 152, 431, 163, 409, 2, 11, 13, 61, 20, 47, 12, 59, 158, 419, 157, 421, 29, 93, 71, 593, 244, 247, 41
Offset: 0

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Author

Antti Karttunen, May 29 2021

Keywords

Crossrefs

Cf. also A344761 (another variant based on inverse of A328626).

Programs

  • PARI
    A328627(n) = { my(m=1, p=2, d=0); while(n, d = lift(Mod(n,p)/(d+1)); m *= (p^d); n = n\p; p = nextprime(1+p)); (m); };
    A003415(n) = if(n<=1, 0, my(f=factor(n)); n*sum(i=1, #f~, f[i, 2]/f[i, 1]));
    A003557(n) = (n/factorback(factorint(n)[, 1]));
    A342001(n) = (A003415(n) / A003557(n));
    A344762(n) = A342001(A328627(n));

Formula

a(n) = A342001(A328627(n)) = A342002(A328626(n)).