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.

A317946 Additive with a(p^e) = A011371(e); the 2-adic valuation of A317934(n).

Original entry on oeis.org

0, 0, 0, 1, 0, 0, 0, 1, 1, 0, 0, 1, 0, 0, 0, 3, 0, 1, 0, 1, 0, 0, 0, 1, 1, 0, 1, 1, 0, 0, 0, 3, 0, 0, 0, 2, 0, 0, 0, 1, 0, 0, 0, 1, 1, 0, 0, 3, 1, 1, 0, 1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 1, 4, 0, 0, 0, 1, 0, 0, 0, 2, 0, 0, 1, 1, 0, 0, 0, 3, 3, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 1, 0, 0, 0, 3, 0, 1, 1, 2, 0, 0, 0, 1, 0
Offset: 1

Views

Author

Antti Karttunen, Aug 24 2018

Keywords

Comments

Records are A005187, occurring at A000302 (powers of 4).

Crossrefs

Programs

  • Mathematica
    f[p_, e_] := e - DigitCount[e, 2, 1]; a[1] = 0; a[n_] := Plus @@ f @@@ FactorInteger[n]; Array[a, 100] (* Amiram Eldar, Jan 21 2024 *)
  • PARI
    A011371(n) = (n - hammingweight(n));
    A317934(n) = vecsum(apply(e -> A011371(e),factor(n)[,2]));

Formula

a(n) = A007814(A317934(n)).
Asymptotic mean: Limit_{m->oo} (1/m) * Sum_{k=1..m} a(k) = Sum_{p prime, k>=1} 1/(p^(2^k) - 1) = 0.63710219855356676263... . - Amiram Eldar, Jan 21 2024