OFFSET
0,4
LINKS
Alois P. Heinz, Table of n, a(n) for n = 0..700
FORMULA
a(n) = Sum_{k>=1} k * A247749(n,k).
MAPLE
b:= proc(x, y) option remember; `if`(y<0 or x<y, 0,
`if`(x=0, [1, 0], add((p->p+[0, p[1]*(y+j/2)])
(b(x-1, y+j)), j=[-1, -3, 0, 1, 3])))
end:
a:= n-> b(n, 0)[2]:
seq(a(n), n=0..30);
MATHEMATICA
b[x_, y_] := b[x, y] = If[y < 0 || x < y, {0, 0},
If[x == 0, {1, 0}, Sum[Function[p, p + {0, p[[1]]*(y + j/2)}][
b[x - 1, y + j]], {j, {-1, -3, 0, 1, 3}}]]];
a[n_] := b[n, 0][[2]];
Table[a[n], {n, 0, 30}] (* Jean-François Alcover, Apr 29 2022, after Alois P. Heinz *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Sep 23 2014
STATUS
approved