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%I #9 Jul 03 2018 02:42:42
%S 0,0,0,0,1,4,16,51,158,463,1330,3742,10438,28877,79619,218997,602079,
%T 1655623,4557604,12564084,34697544,96006605,266185703,739530680,
%U 2058786037,5742859294,16050179897,44939957405,126052336580,354158412141
%N Number of "nonlinear" trees on n nodes.
%H J. H. Verner, <a href="https://doi.org/10.1016/S0168-9274(96)00041-4">High-order explicit Runge-Kutta pairs with low stage order</a>, Applied Numerical Mathematics, 22 (1996), 345-347. See Table 2.
%F a(n) = 0 for n <= 4. Thereafter, a(n) = A000081(n) - (n-1) - A000295(n-2) = A000081(n) - 2^(n-2). For example, a(9) = 286 - 8 - 120 = 286 - 2^7 = 158.
%Y Cf. A000081, A000295.
%K nonn
%O 1,6
%A _N. J. A. Sloane_, Jul 02 2018, following a suggestion from Chris Kennedy, Jun 24 2018
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