OFFSET
12,1
LINKS
Joerg Arndt and Alois P. Heinz, Table of n, a(n) for n = 12..1000
EXAMPLE
a(12) = 5: [3,2,1,3,2,1], [2,1,2,1,3,2,1], [2,1,3,2,1,2,1], [3,2,1,2,1,2,1], [2,1,2,1,2,1,2,1].
MAPLE
b:= proc(n, i) option remember;
`if`(n=0, 1, convert(series(add(b(n-j, j)*
`if`(j<i, x, 1), j=1..n), x, 5), polynom))
end:
a:= n-> coeff(b(n, 0), x, 4):
seq(a(n), n=12..50);
MATHEMATICA
k = 4;
b[n_, i_] := b[n, i] = If[n == 0, 1, Sum[b[n - j, j]*
If[j < i, x, 1], {j, n}] + O[x]^(k + 1)];
a[n_] := SeriesCoefficient[b[n, 0], {x, 0, k}];
a /@ Range[12, 50] (* Jean-François Alcover, Aug 27 2021, after Maple code *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Joerg Arndt and Alois P. Heinz, Apr 26 2014
STATUS
approved