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.

A329642 a(n) = Sum_{d|n} [1 == A008683(n/d)] * A323244(d), where A323244(x) gives the deficiency of A156552(x).

Original entry on oeis.org

0, 1, 1, 2, 1, 4, 1, 6, 0, 5, 1, 11, 1, 16, 2, 6, 1, 13, 1, 19, -3, 18, 1, 24, -4, 46, 4, 23, 1, 13, 1, 30, 14, 82, -2, 18, 1, 256, -12, 24, 1, 39, 1, 67, 9, 226, 1, 52, -12, 20, 8, 131, 1, 28, -19, 72, -12, 748, 1, 53, 1, 1362, 17, 22, 10, 45, 1, 215, 254, 43, 1, 48, 1, 3838, 11, 407, -10, 109, 1, 84, -12, 5458, 1, 48, -72, 12250, -348, 32, 1, 18
Offset: 1

Views

Author

Antti Karttunen, Nov 21 2019

Keywords

Crossrefs

Cf. A329645 (inverse Möbius transform).

Programs

  • PARI
    A156552(n) = {my(f = factor(n), p2 = 1, res = 0); for(i = 1, #f~, p = 1 << (primepi(f[i, 1]) - 1); res += (p * p2 * (2^(f[i, 2]) - 1)); p2 <<= f[i, 2]); res}; \\ From A156552
    A323243(n) = if(1==n,0,sigma(A156552(n)));
    A329642(n) = sumdiv(n,d,(1==moebius(n/d))*((2*A156552(d))-A323243(d)));

Formula

a(n) = Sum_{d|n} [1 == A008683(n/d)] * (2*A156552(d) - A323243(d)).
a(n) = A329643(n) + A329644(n).