3,2

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

S. Plouffe, Approximations de S\'{e}ries G\'{e}n\'{e}ratrices et Quelques Conjectures, Dissertation, Universit\'{e} du Qu\'{e}bec \`{a} Montr\'{e}al, 1992.

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.

T. D. Noe, Table of n, a(n) for n=3..100

S. Plouffe, Approximations de S\'{e}ries G\'{e}n\'{e}ratrices et Quelques Conjectures, Dissertation, Universit\'{e} du Qu\'{e}bec \`{a} Montr\'{e}al, 1992.

S. Plouffe, 1031 Generating Functions and Conjectures, Universit\'{e} du Qu\'{e}bec \`{a} Montr\'{e}al, 1992.

G.f.: z^3/((1-z)(1-3z)(1-9z)(1-27z)); a(n) = (27^n - 13*9^n + 39*3^n - 27)/11232 - Mitch Harris (maharri(AT)gmail.com), Mar 23 2008

A006101:=1/(z-1)/(3*z-1)/(27*z-1)/(9*z-1); [S. Plouffe in his 1992 dissertation, assuming offset zero.]

(Other) sage: [gaussian_binomial(n, 3, 3) for n in xrange(3, 17)] # [From Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), May 25 2009]

Sequence in context: A004385 A152257 A061650 this_sequence A049396 A135644 A165371

Adjacent sequences: A006098 A006099 A006100 this_sequence A006102 A006103 A006104

nonn

N. J. A. Sloane (njas(AT)research.att.com).

Removed attribute "conjectured" from Plouffe G.f R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Mar 11 2009