2,2

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.

G.f.: 1/[(1-x)(1+12x)(1-144x)].

Adjacent sequences: A015261 A015262 A015263 this_sequence A015265 A015266 A015267

Sequence in context: A133240 A129050 A129049 this_sequence A055579 A061491 A048128

nonn,easy

Olivier Gerard (olivier.gerard(AT)gmail.com)