A259863 Number of rooted highly irregular trees with n nodes.

1, 1, 0, 2, 0, 0, 0, 4, 9, 5, 0, 0, 0, 7, 15, 16, 34, 72, 133, 250, 399, 572, 828, 1176, 1700, 2509, 3456, 4494, 5887, 7980, 11625, 18064, 28710, 46665, 77070, 127187, 209300, 341674, 550078, 873272

Offset

1,4

Links

Table of n, a(n) for n=1..40.

Alavi, Yousef, Gary Chartrand, Fan RK Chung, Paul Erdős, Ronald L. Graham, and Ortrud R. Oellermann, Highly irregular graphs, Journal of Graph Theory, 11, no. 2 (1987): 235-249.

K. A. McKeon, Letter to N. J. A. Sloane, Jul 25 1991. Gives a(n) for n <= 40.

Crossrefs

Cf. A259864.

Sequence in context: A348513 A110173 A328820 * A283666 A131427 A153198

Adjacent sequences: A259860 A259861 A259862 * A259864 A259865 A259866

Keyword

nonn,more

Author

N. J. A. Sloane, Jul 08 2015

Status

approved