9,2

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: A157798 A051470 A076135 this_sequence A115385 A122532 A015394

Adjacent sequences: A015379 A015380 A015381 this_sequence A015383 A015384 A015385

sign,easy

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