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.

A353372 Inverse Möbius transform of A353370.

Original entry on oeis.org

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

Views

Author

Antti Karttunen, Apr 16 2022

Keywords

Comments

Number of terms of A325698 that divide n.

Crossrefs

Programs

  • PARI
    A353370(n) = { my(f = factor(n)); (0==sum(i=1, #f~, f[i,2]*((-1)^(primepi(f[i, 1])%2)))); };
    A353372(n) = sumdiv(n,d,A353370(d));

Formula

a(n) = Sum_{d|n} A353370(d).
a(n) = A000005(n) - A353371(n).
a(p) = 1 for all primes p.
a(n) = a(A003961(n)) = a(A348717(n)), for all n >= 1.