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.

A130089 a(n) = denominator of Product_{k=1..n} k^mu(n+1-k), where mu(k) = A008683(k).

Original entry on oeis.org

1, 1, 2, 3, 12, 20, 45, 14, 70, 864, 525, 880, 6237, 3328, 3003, 900, 25025, 60928, 53703, 19456, 3997125, 1209600, 3556553, 30912, 67643667, 11264000, 244375, 26687232, 52055003, 2702336, 351469125, 90272000, 47453715, 1284636672
Offset: 1

Views

Author

Leroy Quet, May 06 2007

Keywords

Examples

			a(5) = denominator(1^(-1)*2^(0)*3^(-1)*4^(-1)*5^(1)) = denominator(5/12) = 12.
		

Crossrefs

Programs

  • Maple
    with(numtheory): a:=n->denom(mul(k^mobius(n+1-k),k=1..n)): seq(a(n),n=1..41); # Emeric Deutsch, May 09 2007
  • PARI
    a(n) = denominator(prod(k=1, n, k^moebius(n+1-k))); \\ Michel Marcus, Feb 12 2019

Extensions

More terms from Emeric Deutsch, May 09 2007