7,2

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: A083614 A114675 A102501 this_sequence A100383 A107447 A133183

Adjacent sequences: A015343 A015344 A015345 this_sequence A015347 A015348 A015349

sign,easy

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