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.

A324489 a(n) = A324488(n)/n.

Original entry on oeis.org

1, 0, 21, 31, 266, 672, 3484, 11375, 48768, 177023, 716418, 2730315, 10878520, 42485638, 169181010, 670042125, 2678678730, 10705526976, 43007270292, 173003915322, 698235680844, 2822901487191, 11439823946306, 46438021798875, 188856966693230, 769224288476860, 3137871076604544, 12817404260955810
Offset: 1

Views

Author

N. J. A. Sloane, Mar 12 2019

Keywords

Crossrefs

Programs

  • PARI
    a001350(n) = fibonacci(n+1)+fibonacci(n-1)-1-(-1)^n;
    a(n) = sumdiv(n, d, moebius(n/d)*a001350(d)^3)/n; \\ Seiichi Manyama, Apr 29 2021
    
  • PARI
    f(x) = ((1-3*x+x^2)*(1+3*x+x^2))^3*(1-x^2)^10/((1-4*x-x^2)*(1-x-x^2)^6*(1+x-x^2)^9);
    my(N=40, x='x+O('x^N)); Vec(sum(k=1, N, moebius(k)*log(f(x^k))/k)) \\ Seiichi Manyama, Apr 29 2021

Formula

From Seiichi Manyama, Apr 29 2021: (Start)
a(n) = (1/n) * Sum_{d|n} mu(n/d) * A001350(d)^3 = (1/n) * Sum_{d|n} mu(n/d) * A324487(d).
G.f.: Sum_{k>=1} mu(k) * log(f(x^k))/k , where f(x) = ((1-3*x+x^2) * (1+3*x+x^2))^3 * (1-x^2)^10/((1-4*x-x^2) * (1-x-x^2)^6 * (1+x-x^2)^9). (End)

Extensions

More terms from Seiichi Manyama, Apr 29 2021