1,6

R. P. Stanley, Enumerative Combinatorics, Cambridge, Vol. 2, 1999; see Problem 7.2(d).

Table of n, a(n) for n=1..84.

Sequence in context: A104147 A227568 A232746 * A097882 A108955 A108956

Adjacent sequences: A052143 A052144 A052145 * A052147 A052148 A052149

nonn

N. J. A. Sloane, Jan 23 2000

approved