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.

A190153 Row sums of the triangle A190152.

Original entry on oeis.org

1, 2, 12, 65, 351, 1897, 10252, 55405, 299426, 1618192, 8745217, 47261895, 255418101, 1380359512, 7459895657, 40315615410, 217878227876, 1177482265857, 6363483400447, 34390259761825, 185855747875876, 1004422742303477, 5428215467030962
Offset: 0

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Author

Emanuele Munarini, May 05 2011

Keywords

Crossrefs

Programs

  • Magma
    I:=[1, 2, 12]; [n le 3 select I[n] else 5*Self(n-1) +2*Self(n-2) + Self(n-3): n in [1..30]]; // G. C. Greubel, Dec 30 2017
  • Maple
    seq(add(binomial(3*n-k,3*n-3*k), k=0..n), n=0..20);
  • Mathematica
    Table[Sum[Binomial[3n - k, 3n - 3k], {k, 0, n}], {n, 0, 22}]
    LinearRecurrence[{5,2,1}, {1,2,12}, 30] (* G. C. Greubel, Dec 30 2017 *)
  • Maxima
    makelist(sum(binomial(3*n-k,3*n-3*k),k,0,n),n,0,22);
    
  • PARI
    x='x+O('x^30); Vec((1-3*x)/(1-5*x-2*x^2-x^3)) \\ G. C. Greubel, Dec 30 2017
    

Formula

a(n) = Sum_{k=0..n} binomial(3*n-k,3*n-3*k).
From Colin Barker, Mar 21 2012: (Start)
a(n) = 5*a(n-1) + 2*a(n-2) + a(n-3).
G.f.: (1-3*x)/(1-5*x-2*x^2-x^3). (End)