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.

A373986 Numerator of A373158(n) / A108951(n), where A108951 is fully multiplicative and A373158 is fully additive with a(p) = p# for prime p, where x# is the primorial A034386(x).

Original entry on oeis.org

0, 1, 1, 1, 1, 2, 1, 3, 1, 8, 1, 5, 1, 53, 1, 1, 1, 7, 1, 17, 6, 578, 1, 1, 1, 7508, 1, 107, 1, 19, 1, 5, 193, 127628, 4, 1, 1, 2424923, 2503, 3, 1, 109, 1, 1157, 7, 55773218, 1, 7, 1, 31, 14181, 15017, 1, 5, 13, 9, 269436, 1617423308, 1, 1, 1, 50140122533, 37, 3, 167, 1159, 1, 255257, 18591073, 121, 1, 1, 1, 1855184533703
Offset: 1

Views

Author

Antti Karttunen, Jun 25 2024

Keywords

Crossrefs

Cf. A108951, A373158, A373985, A373987 (denominators), A373988 (rgs-transform).

Programs

  • PARI
    A373986(n) = { my(f=factor(n),m=1,s=0); for(i=1, #f~, my(x=prod(i=1,primepi(f[i, 1]),prime(i))); s += f[i, 2]*x; m *= x^f[i, 2]); s/gcd(m,s); };
    
  • PARI
    A373986(n) = numerator(A373158(n)/A108951(n));

Formula

a(n) = A373158(n) / A373985(n) = A373158(n) / gcd(A108951(n), A373158(n)).