12,2

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: A017411 A017531 A066543 this_sequence A017184 A017280 A017520

Adjacent sequences: A015430 A015431 A015432 this_sequence A015434 A015435 A015436

nonn,easy

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