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A243231 Number of isoscent sequences of length n with exactly five ascents. 2
53, 2751, 56905, 771451, 8134377, 72508373, 573143602, 4140884203, 27910175578, 178061795837, 1086790574778, 6397136152382, 36542124316824, 203563522508400, 1110216333288652, 5946996009211010, 31369110229193995, 163289639236069520, 840329677373681576 (list; graph; refs; listen; history; text; internal format)
OFFSET

9,1

LINKS

Joerg Arndt and Alois P. Heinz, Table of n, a(n) for n = 9..100

MAPLE

b:= proc(n, i, t) option remember; `if`(n<1, 1, expand(add(

`if`(j>i, x, 1) *b(n-1, j, t+`if`(j=i, 1, 0)), j=0..t+1)))

end:

a:= n-> coeff(b(n-1, 0$2), x, 5):

seq(a(n), n=9..35);

MATHEMATICA

b[n_, i_, t_] := b[n, i, t] = If[n < 1, 1, Expand[Sum[

If[j > i, x, 1] *b[n - 1, j, t + If[j == i, 1, 0]], {j, 0, t + 1}]]];

a[n_] := Coefficient[b[n - 1, 0, 0], x, 5];

Table[a[n], {n, 9, 35}] (* Jean-François Alcover, Aug 27 2021, after Maple code *)

CROSSREFS

Column k=5 of A242351.

Sequence in context: A221237 A059694 A263516 * A280357 A300406 A013542

Adjacent sequences: A243228 A243229 A243230 * A243232 A243233 A243234

KEYWORD

nonn

AUTHOR

Joerg Arndt and Alois P. Heinz, Jun 01 2014

STATUS

approved

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Last modified February 7 16:06 EST 2023. Contains 360128 sequences. (Running on oeis4.)