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.

A015397 Gaussian binomial coefficient [ n,10 ] for q=-9.

Original entry on oeis.org

1, 3138105961, 11078672649879436966, 38576026619154398792076180886, 134526791875519431052113309866825757301, 469057975890128020293538941741406421614821552253, 1635507110993502253670495254060345828123783573932476807608
Offset: 10

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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.

Crossrefs

Cf. Gaussian binomial coefficients [n, 10] for q = -2..-13: A015386, A015388, A015390, A015391, A015392, A015393, A015394, A015398, A015399, A015401, A015402. - Vincenzo Librandi, Nov 04 2012

Programs

  • Magma
    r:=10; q:=-9; [&*[(1-q^(n-i+1))/(1-q^i): i in [1..r]]: n in [r..25]]; // Vincenzo Librandi, Nov 04 2012
  • Mathematica
    Table[QBinomial[n, 10, -9], {n, 10, 20}] (* Vincenzo Librandi, Nov 04 2012 *)
  • Sage
    [gaussian_binomial(n,10,-9) for n in range(10,16)] # Zerinvary Lajos, May 25 2009
    

Formula

a(n) = Product_{i=1..10} ((-9)^(n-i+1)-1)/((-9)^i-1) (by definition). - Vincenzo Librandi, Nov 04 2012