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.

A015429 Gaussian binomial coefficient [ n,12 ] for q=-6.

Original entry on oeis.org

1, 1865813431, 4177511710786827427, 9051628015237517688012698587, 19718638974813744289323111717093729163, 42917665763197914342331213431251480044434903403
Offset: 12

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References

  • J. Goldman and G.-C. Rota, The number of subspaces of a vector space, pp. 75-83 of W. T. Tutte, editor, Recent Progress in Combinatorics. Academic Press, NY, 1969.
  • I. P. Goulden and D. M. Jackson, Combinatorial Enumeration. Wiley, NY, 1983, p. 99.
  • M. Sved, Gaussians and binomials, Ars. Combinatoria, 17A (1984), 325-351.

Programs

  • Magma
    r:=12; q:=-6; [&*[(1-q^(n-i+1))/(1-q^i): i in [1..r]]: n in [r..20]]; // Vincenzo Librandi, Nov 06 2012
  • Mathematica
    Table[QBinomial[n, 12, -6], {n, 12, 20}] (* Vincenzo Librandi, Nov 06 2012 *)
  • Sage
    [gaussian_binomial(n,12,-6) for n in range(12,18)] # Zerinvary Lajos, May 28 2009
    

Formula

a(n) = Product_{i=1..12} ((-6)^(n-i+1)-1)/((-6)^i-1). - Vincenzo Librandi, Nov 06 2012