A006109 Gaussian binomial coefficient [ n,n/2 ] for q=4.

1, 1, 5, 21, 357, 5797, 376805, 24208613, 6221613541, 1594283908581, 1634141006295525, 1673768626404966885, 6857430062381149327845, 28089747579101385828291045, 460250514083576206796548772325, 7540859480106603961931048583270885

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..80
• M. Sved, Gaussians and binomials, Ars. Combinatoria, 17A (1984), 325-351. (Annotated scanned copy)

Programs

Mathematica

Table[QBinomial[n, Floor[n/2], 4], {n, 0, 20}] (* Vincenzo Librandi, Aug 13 2016 *)