5,2

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: A015318 A015319 A015320 this_sequence A015322 A015323 A015324

Sequence in context: A132660 A103808 A029568 this_sequence A069314 A022208 A122036

sign,easy

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