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: A029824 A067388 A034612 this_sequence A034644 A104329 A104333

Adjacent sequences: A015352 A015353 A015354 this_sequence A015356 A015357 A015358

sign,easy

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