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.

A339812 Number of prime divisors of (A019565(n) - 1), counted with multiplicity.

Original entry on oeis.org

0, 1, 1, 2, 2, 2, 1, 2, 1, 3, 1, 2, 2, 4, 2, 2, 2, 5, 2, 4, 1, 3, 2, 3, 3, 3, 1, 8, 1, 2, 1, 3, 2, 2, 2, 6, 2, 2, 1, 4, 1, 5, 2, 2, 3, 4, 1, 2, 3, 3, 1, 4, 1, 6, 1, 6, 3, 3, 2, 5, 1, 2, 1, 4, 2, 3, 1, 4, 2, 2, 1, 2, 2, 3, 2, 5, 2, 4, 2, 3, 1, 6, 2, 2, 3, 3, 2, 4, 1, 3, 1, 5, 2, 2, 2, 4, 4, 2, 3, 6, 2, 2, 2, 2, 2
Offset: 1

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Author

Antti Karttunen, Dec 18 2020

Keywords

Crossrefs

Programs

  • PARI
    A019565(n) = { my(m=1, p=1); while(n>0, p = nextprime(1+p); if(n%2, m *= p); n >>= 1); (m); };
    A339812(n) = bigomega(A019565(n)-1);

Formula

a(n) = A001222(A339809(n)) = A001222(A019565(n)-1).
a(n) = A001222(A339810(n)).