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.

A378211 Dirichlet inverse of A191161, hypersigma variant 2.

Original entry on oeis.org

1, -4, -5, 4, -7, 18, -9, 0, 6, 26, -13, -16, -15, 34, 33, 0, -19, -18, -21, -24, 43, 50, -25, 0, 10, 58, 0, -32, -31, -114, -33, 0, 63, 74, 61, 12, -39, 82, 73, 0, -43, -150, -45, -48, -36, 98, -49, 0, 14, -30, 93, -56, -55, 0, 89, 0, 103, 122, -61, 96, -63, 130, -48, 0, 103, -222, -69, -72, 123, -218, -73, 0, -75
Offset: 1

Views

Author

Antti Karttunen, Nov 22 2024

Keywords

Crossrefs

Cf. A191161.
Cf. also A378210.

Programs

  • PARI
    A191161(n) = sumdiv(n, d, if(dA191161(d), n));
    memoA378211 = Map();
    A378211(n) = if(1==n,1,my(v); if(mapisdefined(memoA378211,n,&v), v, v = -sumdiv(n,d,if(dA191161(n/d)*A378211(d),0)); mapput(memoA378211,n,v); (v)));

Formula

a(1) = 1, and for n > 1, a(n) = -Sum_{d|n, dA191161(n/d) * a(d).