8,2

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: A022209 A064871 A054852 this_sequence A108841 A124490 A124491

Adjacent sequences: A015358 A015359 A015360 this_sequence A015362 A015363 A015364

nonn,easy

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