A130132 Number of trees on n vertices which are not lobsters.

0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 4, 19, 77, 287, 1002, 3365, 10853, 34088, 104574, 315116, 935321, 2743374, 7966723, 22951010, 65681536, 186961873, 529845497, 1496245171, 4213181063, 11836671278, 33195092417, 92966480736

Offset

1,11

Comments

Also the number of nonlinear trees on n nodes. - Andrew Howroyd, Dec 17 2020

Links

Andrew Howroyd, Table of n, a(n) for n = 1..200

Tanay Wakhare, Eric Wityk, and Charles R. Johnson, The proportion of trees that are linear, Discrete Mathematics, 343.10 (2020): 112008. Also on arXiv, arXiv:1901.08502 [math.CO], 2019-2020. See Tables 1 and 2 (but beware errors).

Eric Weisstein's World of Mathematics, Lobster Graph

Formula

a(n) = A000055(n) - A130131(n). - Andrew Howroyd, Nov 02 2017

Crossrefs

Cf. A000055, A130131, A331693.

Sequence in context: A167478 A094734 A094578 * A037590 A359087 A037681

Adjacent sequences: A130129 A130130 A130131 * A130133 A130134 A130135

Keyword

nonn

Author

Eric W. Weisstein, May 11 2007

Extensions

a(15)-a(32) from Washington Bomfim, Feb 23 2011

Status

approved