This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A291825 Number of ordered rooted trees with n non-root nodes and all outdegrees <= ten. 2
 1, 1, 2, 5, 14, 42, 132, 429, 1430, 4862, 16796, 58785, 207999, 742795, 2673760, 9690969, 35337321, 129543843, 477158000, 1765043115, 6554105415, 24421914855, 91289026931, 342225162126, 1286341683924, 4846861938006, 18303921153521, 69268371485362, 262644901975126 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 COMMENTS Also the number of Dyck paths of semilength n with all ascent lengths <= ten. Also the number of permutations p of [n] such that in 0p all up-jumps are <= ten and no down-jump is larger than 1. An up-jump j occurs at position i in p if p_{i} > p_{i-1} and j is the index of p_i in the increasingly sorted list of those elements in {p_{i}, ..., p_{n}} that are larger than p_{i-1}. A down-jump j occurs at position i in p if p_{i} < p_{i-1} and j is the index of p_i in the decreasingly sorted list of those elements in {p_{i}, ..., p_{n}} that are smaller than p_{i-1}. First index in the lists is 1 here. Differs from A000108 first at n = 11. LINKS Alois P. Heinz, Table of n, a(n) for n = 0..1000 N. Hein and J. Huang, Modular Catalan Numbers, arXiv:1508.01688 [math.CO], 2015 FORMULA G.f.: G(x)/x where G(x) is the reversion of x*(1-x)/(1-x^11). - Andrew Howroyd, Dec 01 2017 MAPLE b:= proc(u, o) option remember; `if`(u+o=0, 1,       add(b(u-j, o+j-1), j=1..min(1, u))+       add(b(u+j-1, o-j), j=1..min(10, o)))     end: a:= n-> b(0, n): seq(a(n), n=0..30); MATHEMATICA b[u_, o_, k_] := b[u, o, k] = If[u + o == 0, 1, Sum[b[u - j, o + j - 1, k], {j, 1, Min[1, u]}] + Sum[b[u + j - 1, o - j, k], {j, 1, Min[k, o]}]]; a[n_] := b[0, n, 10]; Table[a[n], {n, 0, 30}] (* Jean-François Alcover, Nov 07 2017, after Alois P. Heinz *) PROG (PARI) Vec(serreverse(x*(1-x)/(1-x*x^10) + O(x*x^25))) \\ Andrew Howroyd, Nov 29 2017 CROSSREFS Column k=10 of A288942. Cf. A000108. Sequence in context: A261592 A291824 A287973 * A287974 A115140 A120588 Adjacent sequences:  A291822 A291823 A291824 * A291826 A291827 A291828 KEYWORD nonn AUTHOR Alois P. Heinz, Sep 01 2017 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified October 17 19:36 EDT 2018. Contains 316293 sequences. (Running on oeis4.)