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A243237
Number of isoscent sequences of length n with maximal number of ascents.
2
1, 1, 1, 4, 3, 25, 17, 2, 172, 53, 7, 1422, 436, 72, 5, 7894, 1854, 271, 19, 86372, 19919, 3179, 312, 14, 527951, 102503, 14324, 1287, 56, 7237537, 1373018, 198783, 20572, 1350, 42, 48862041, 8055893, 1032239, 96532, 5866, 174, 801902467, 129068117, 16767855
OFFSET
0,4
LINKS
Joerg Arndt and Alois P. Heinz, Table of n, a(n) for n = 0..100
FORMULA
a(n) = A242351(n,n+3-ceiling(2*sqrt(n+2))).
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-> (p-> coeff(p, x, degree(p)))(b(n-1, 0$2)):
seq(a(n), n=0..50);
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_] := With[{p = b[n - 1, 0, 0]}, Coefficient[p, x, Exponent[p, x]]];
Table[a[n], {n, 0, 50}] (* Jean-François Alcover, Aug 27 2021, after Maple code *)
CROSSREFS
Sequence in context: A286328 A189742 A350173 * A072044 A376607 A286795
KEYWORD
nonn
AUTHOR
Joerg Arndt and Alois P. Heinz, Jun 01 2014
STATUS
approved