A006115 Gaussian binomial coefficient [ n,n/2 ] for q=5.

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

Offset: 0

Author

N. J. A. Sloane

Keywords

• nonn

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)

Programs

Mathematica

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