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.

A323155 a(n) = Product_{d|n, d-1 is prime} (d-1)^(1+A286561(n,d-1)), where A286561(n,k) gives the k-valuation of n (for k > 1).

Original entry on oeis.org

1, 1, 2, 3, 1, 20, 1, 21, 2, 1, 1, 3960, 1, 13, 2, 21, 1, 340, 1, 57, 2, 1, 1, 1275120, 1, 1, 2, 39, 1, 2900, 1, 651, 2, 1, 1, 201960, 1, 37, 2, 399, 1, 10660, 1, 129, 2, 1, 1, 119861280, 1, 1, 2, 3, 1, 18020, 1, 1911, 2, 1, 1, 643678200, 1, 61, 2, 651, 1, 20, 1, 201, 2, 13, 1, 4617209520, 1, 73, 2, 111, 1, 20, 1, 31521, 2, 1, 1, 175186440, 1, 1, 2, 903, 1
Offset: 1

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Author

Antti Karttunen, Jan 09 2019

Keywords

Crossrefs

Programs

  • PARI
    A323155(n) = { my(m=1); fordiv(n, d, if(isprime(d-1), m *= (d-1)^(1+valuation(n,d-1)))); (m); }; \\ Antti Karttunen, Jan 09 2019

Formula

a(n) = Product_{d|n, d>2} [(d-1)^(1+A286561(n,d-1))]^A010051(d-1).