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.

A353467 a(1) = 1, for n > 1, a(n) = -Sum_{d|n, dA252463(n/d)) * a(d).

Original entry on oeis.org

1, -1, 1, 2, -1, -3, 1, -5, -1, 3, -1, 10, 1, -3, 1, 14, -1, 0, 1, -10, -1, 3, -1, -35, 2, -3, 2, 10, 1, 3, -1, -42, 1, 3, -3, 10, 1, -3, -1, 35, -1, -3, 1, -10, -3, 3, -1, 126, -1, -9, 1, 10, 1, -1, 3, -35, -1, -3, -1, -30, 1, 3, 3, 132, -3, 3, -1, -10, 1, 15, 1, -70, -1, -3, -1, 10, 1, -3, 1, -126, -5, 3, -1, 30
Offset: 1

Views

Author

Antti Karttunen, Apr 21 2022

Keywords

Crossrefs

Cf. A000040, A252463, A353468 [Dirichlet inverse, also a(A252463(n))], A353469 [sum with it].
Cf. also A353457.

Programs

  • PARI
    A252463(n) = if(!(n%2),n/2,my(f=factor(n)); for(i=1, #f~, f[i,1] = precprime(f[i,1]-1)); factorback(f));
    memoA353467 = Map();
    A353467(n) = if(1==n,1,my(v); if(mapisdefined(memoA353467,n,&v), v, v = -sumdiv(n,d,if(dA353467(A252463(n/d))*A353467(d),0)); mapput(memoA353467,n,v); (v)));

Formula

a(1) = 1, for n > 1, a(n) = -Sum_{d|n, dA353468(n/d) * a(d).
For all n >= 1, a(A000040(n)) = ((-1)^n).