A006115 Gaussian binomial coefficient [ n,n/2 ] for q=5. (Formerly M4211)

1, 1, 6, 31, 806, 20306, 2558556, 320327931, 200525284806, 125368356709806, 391901483074853556, 1224770494838892134806, 19138263752352528498478556, 299039198587280398947721603556, 23362736428829868448189697999416056, 1825218456001772231793929085435472462931

Offset

0,3

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.

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

M. Sved, Gaussians and binomials, Ars. Combinatoria, 17A (1984), 325-351.

Links

Vincenzo Librandi, Table of n, a(n) for n = 0..75

M. Sved, Gaussians and binomials, Ars. Combinatoria, 17A (1984), 325-351. (Annotated scanned copy)

Mathematica

Table[QBinomial[n, Floor[n/2], 5], {n, 0, 20}] (* Vincenzo Librandi, Aug 13 2016 *)

Crossrefs

Sequence in context: A144576 A120107 A015462 * A144780 A126976 A045159

Adjacent sequences: A006112 A006113 A006114 * A006116 A006117 A006118

Keyword

nonn

Author

N. J. A. Sloane

Status

approved