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.

A359815 Dirichlet inverse of A359770, where A359770(n) = 1 if n and bigomega(n) are of different parity, otherwise 0.

Original entry on oeis.org

1, -1, 0, 1, 0, 0, 0, -2, -1, 0, 0, -1, 0, 0, -1, 3, 0, 1, 0, -1, -1, 0, 0, 2, -1, 0, 0, -1, 0, 1, 0, -5, -1, 0, -1, -1, 0, 0, -1, 2, 0, 1, 0, -1, 0, 0, 0, -4, -1, 1, -1, -1, 0, 0, -1, 2, -1, 0, 0, -1, 0, 0, 0, 8, -1, 1, 0, -1, -1, 1, 0, 2, 0, 0, 0, -1, -1, 1, 0, -4, 0, 0, 0, -1, -1, 0, -1, 2, 0, 0, -1, -1, -1, 0, -1, 8
Offset: 1

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Author

Antti Karttunen, Jan 15 2023

Keywords

Crossrefs

Cf. A001222, A069345, A353556, A353557, A359770, A359816 (parity of terms), A359817 (positions of odd terms).
Cf. also A358777 (Dirichlet inverse of A353557), A359763 [= a(A003961(n))], A359814.

Programs

  • PARI
    A359770(n) = ((n-bigomega(n))%2);
    memoA359815 = Map();
    A359815(n) = if(1==n,1,my(v); if(mapisdefined(memoA359815,n,&v), v, v = -sumdiv(n,d,if(dA359770(n/d)*A359815(d),0)); mapput(memoA359815,n,v); (v)));

Formula

a(1) = 1, and for n > 1, a(n) = -Sum_{d|n, dA359770(n/d) * a(d).