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.

A099132 Quintisection of 1/(1-x^5-x^6).

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 2, 7, 22, 57, 127, 253, 464, 804, 1354, 2289, 4005, 7372, 14198, 28033, 55523, 108699, 208982, 394555, 734561, 1357136, 2504932, 4643816, 8671852, 16313856, 30855957, 58502733, 110882143, 209689343, 395358538, 743376838
Offset: 0

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Author

Paul Barry, Sep 29 2004

Keywords

Crossrefs

Programs

  • Mathematica
    LinearRecurrence[{5,-10,10,-5,1,1},{1,1,1,1,1,1},40] (* Harvey P. Dale, Aug 20 2012 *)
  • PARI
    Vec((1-x)^4/((1-x)^5-x^6) + O(x^40)) \\ Michel Marcus, Sep 06 2017

Formula

G.f.: (1-x)^4/((1-x)^5-x^6);
a(n) = Sum_{k=0..n} binomial(k, 5(n-k));
a(n) = 5a(n-1)-10a(n-2)+10a(n-3)-5a(n-4)+a(n-5)+a(n-6);
a(n) = A017837(5n).
a(n) = Sum_{k=0..floor(n/5)} binomial(n-k, 5k). - Paul Barry, May 09 2005