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.

A349368 Dirichlet inverse of A006369, the inverse permutation of "amusical permutation".

Original entry on oeis.org

1, -3, -2, 4, -7, 8, -9, -8, -2, 29, -15, -18, -17, 35, 18, 16, -23, 4, -25, -68, 22, 61, -31, 44, 16, 67, -2, -76, -39, -104, -41, -32, 38, 93, 79, 6, -49, 99, 42, 168, -55, -120, -57, -140, 10, 125, -63, -104, 16, -128, 58, -148, -71, 0, 137, 184, 62, 157, -79, 354, -81, 163, 14, 64, 151, -216, -89, -212, 78, -445
Offset: 1

Views

Author

Antti Karttunen, Nov 17 2021

Keywords

Crossrefs

Cf. also A349351, A349376.

Programs

  • PARI
    A006369(n) = if(!(n%3),(2/3)*n,(1/3)*if(1==(n%3),((4*n)-1),((4*n)+1)));
    memoA349368 = Map();
    A349368(n) = if(1==n,1,my(v); if(mapisdefined(memoA349368,n,&v), v, v = -sumdiv(n,d,if(dA006369(n/d)*A349368(d),0)); mapput(memoA349368,n,v); (v)));

Formula

a(1) = 1; a(n) = -Sum_{d|n, d < n} A006369(n/d) * a(d).
a(n) = A349369(n) - A006369(n).