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 A316321 Number of "nonlinear" trees on n nodes. 0
 0, 0, 0, 0, 1, 4, 16, 51, 158, 463, 1330, 3742, 10438, 28877, 79619, 218997, 602079, 1655623, 4557604, 12564084, 34697544, 96006605, 266185703, 739530680, 2058786037, 5742859294, 16050179897, 44939957405, 126052336580, 354158412141 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,6 LINKS J. H. Verner, High-order explicit Runge-Kutta pairs with low stage order, Applied Numerical Mathematics, 22 (1996), 345-347. See Table 2. FORMULA 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. CROSSREFS Cf. A000081, A000295. Sequence in context: A121184 A203840 A089093 * A058234 A188125 A007688 Adjacent sequences:  A316318 A316319 A316320 * A316322 A316323 A316324 KEYWORD nonn AUTHOR N. J. A. Sloane, Jul 02 2018, following a suggestion from Chris Kennedy, Jun 24 2018 STATUS approved

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Last modified August 4 17:38 EDT 2021. Contains 346454 sequences. (Running on oeis4.)