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.

A022242 Gaussian binomial coefficients [ n,2 ] for q = 8.

Original entry on oeis.org

1, 73, 4745, 304265, 19477641, 1246606473, 79783113865, 5106121684105, 326791806956681, 20914675798619273, 1338539252338766985, 85666512159498155145, 5482656778286418474121, 350890033810959074702473
Offset: 2

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Programs

  • Magma
    r:=2; q:=8; [&*[(1-q^(n-i+1))/(1-q^i): i in [1..r]]: n in [r..20]]; // Vincenzo Librandi, Aug 05 2016
  • Mathematica
    CoefficientList[Series[1/((1-x)(1-8x)(1-64x)), {x,0,25}],x]  (* Harvey P. Dale, Mar 13 2011 *)
    Table[QBinomial[n, 2, 8], {n, 2, 20}] (* Vincenzo Librandi, Aug 05 2016 *)
  • Sage
    [gaussian_binomial(n,2,8) for n in range(2,16)] # Zerinvary Lajos, May 28 2009
    

Formula

G.f.: x^2/[(1-x)(1-8x)(1-64x)].
a(n) = Product_{i=1..2} (8^(n-i+1)-1)/(8^i-1), by definition. - Vincenzo Librandi, Aug 05 2016

Extensions

Offset changed by Vincenzo Librandi, Aug 05 2016