11,2

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.

Sequence in context: A013965 A036095 A068659 this_sequence A061732 A023046 A034213

Adjacent sequences: A015404 A015405 A015406 this_sequence A015408 A015409 A015410

sign,easy

Olivier Gerard (ogerard(AT)ext.jussieu.fr)