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: A126432 A071372 A129474 this_sequence A034649 A129616 A105006

Adjacent sequences: A015408 A015409 A015410 this_sequence A015412 A015413 A015414

sign,easy

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