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.

Adjacent sequences: A015338 A015339 A015340 this_sequence A015342 A015343 A015344

Sequence in context: A015327 A079230 A111887 this_sequence A089212 A023320 A068760

sign,easy

Olivier Gerard (olivier.gerard(AT)gmail.com)