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 A318520 Number of unlabeled rooted identity trees with n non-binary nodes. 2
 0, 1, 1, 1, 1, 1, 1, 2, 3, 5, 8, 14, 23, 40, 69, 122, 215, 382, 679, 1217, 2185, 3944, 7136, 12958, 23578, 43026, 78673, 144190, 264755, 487074, 897549, 1656697, 3062423, 5669110, 10508397, 19503447, 36240898, 67418514, 125551221, 234047825, 436722486 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,8 LINKS Alois P. Heinz, Table of n, a(n) for n = 0..3501 EXAMPLE a(8) = 3: o o o | | /|\ o o o o o | /|\ | | o o o o o o | | | | o o o o | | | o o o | o | o | o MAPLE b:= proc(n, i, t) option remember; `if`(n=0, `if`(t=1, 0, 1), `if`(i<1, 0, add(b(n-i*j, i-1, max(0, t-j))*binomial(a(i), j), j=0..n/i))) end: a:= n-> `if`(n<2, n, b(n-1\$2, 3)): seq(a(n), n=0..50); CROSSREFS Cf. A000081, A004111, A303023. Sequence in context: A000621 A191317 A218020 * A039828 A357303 A246360 Adjacent sequences: A318517 A318518 A318519 * A318521 A318522 A318523 KEYWORD nonn AUTHOR Alois P. Heinz, Aug 28 2018 STATUS approved

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Last modified February 20 21:52 EST 2024. Contains 370219 sequences. (Running on oeis4.)