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.

A378438 Dirichlet inverse of A378436, where A378436 is the inverse Möbius transform of the number of partitions of n into distinct divisors of n.

Original entry on oeis.org

1, -2, -2, 1, -2, 3, -2, 0, 1, 4, -2, -1, -2, 4, 4, 0, -2, -1, -2, -3, 4, 4, -2, -2, 1, 4, 0, -3, -2, -8, -2, 0, 4, 4, 4, -2, -2, 4, 4, 0, -2, -7, -2, -2, -2, 4, -2, 0, 1, -2, 4, -2, -2, 0, 4, 1, 4, 4, -2, -21, -2, 4, -2, 0, 4, -7, -2, -2, 4, -8, -2, -10, -2, 4, -2, -2, 4, -6, -2, 0, 0, 4, -2, -15, 4, 4, 4, -1, -2
Offset: 1

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Author

Antti Karttunen, Nov 26 2024

Keywords

Comments

Equivalently, Möbius transform of the Dirichlet inverse of A033630.

Crossrefs

Dirichlet inverse of A378436.
Möbius transform of A378437.

Programs

  • PARI
    A033630(n) = if(!n, 1, my(p=1); fordiv(n, d, p *= (1 + 'x^d)); polcoeff(p, n));
    A378436(n) = sumdiv(n,d,A033630(d));
    memoA378438 = Map();
    A378438(n) = if(1==n,1,my(v); if(mapisdefined(memoA378438,n,&v), v, v = -sumdiv(n,d,if(dA378436(n/d)*A378438(d),0)); mapput(memoA378438,n,v); (v)));

Formula

a(1) = 1, and for n > 1, a(n) = -Sum_{d|n, dA378436(n/d) * a(d).
a(n) = Sum_{d|n} A008683(n/d)*A378437(d).