5,2

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.

Adjacent sequences: A015303 A015304 A015305 this_sequence A015307 A015308 A015309

Sequence in context: A023904 A035839 A048546 this_sequence A028676 A133609 A030465

sign,easy

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