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.

A234507 4*binomial(9*n+4,n)/(9*n+4).

Original entry on oeis.org

1, 4, 42, 580, 9139, 155664, 2791404, 51919296, 992414925, 19375620264, 384734333698, 7745767624560, 157746595917027, 3243956787596560, 67267249849483200, 1404952651131292800, 29529506061314207361, 624113938377564174540, 13256095235994257535900, 282803564653982441429256, 6057302574889055180495805
Offset: 0

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Author

Tim Fulford, Dec 27 2013

Keywords

Comments

Fuss-Catalan sequence is a(n,p,r) = r*binomial(np+r,n)/(np+r), where p=9, r=4.

Crossrefs

Programs

  • Magma
    [1*Binomial(9*n+1, n)/(9*n+1): n in [0..30]];
  • Mathematica
    Table[4 Binomial[9 n + 4, n]/(9 n + 4), {n, 0, 30}]
  • PARI
    a(n) = 4*binomial(9*n+4,n)/(9*n+4);
    
  • PARI
    {a(n)=local(B=1); for(i=0, n, B=(1+x*B^(9/1))^1+x*O(x^n)); polcoeff(B, n)}
    

Formula

G.f. satisfies: B(x) = {1 + x*B(x)^(p/r)}^r, where p=9, r=4.