0,3

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

K. Casteels and B. Stevens, Universal cycles of (n-1)-partitions of an n-set, Discr. Math., 309 (2009), 5332-5340. See Cor. 12 [From N. J. A. Sloane, Sep 15 2009]

J. L. Gross et al., Genus distributions for bouquets of circles, J. Combin. Theory, B 47 (1989), 292-306.

J. L. Gross and J. Yellen, eds., Handbook of Graph Theory, CRC Press, 2004; p. 649.

n*a(n) = 4(2n-3)(n-2)a(n-1).

2^n * (2n-1)!/(n+1)!

Sequence in context: A141011 A090359 A049308 this_sequence A153849 A010792 A064422

Adjacent sequences: A005428 A005429 A005430 this_sequence A005432 A005433 A005434

easy,nonn,nice

Simon Plouffe, N. J. A. Sloane (njas(AT)research.att.com).

Description corrected Apr 15 1998 by Wim van Dam (wimvdam(AT)mildred.physics.ox.ac.uk)