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

Author

Eric W. Weisstein, May 11 2007

Keywords

• nonn

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

Crossrefs

Cf. A000055, A130131, A331693.

Formula

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

Extensions

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