OFFSET
0,8
LINKS
Alois P. Heinz, Table of n, a(n) for n = 0..1000
FORMULA
G.f. A(x) satisfies: A(x) = (1 + x^4 * A(x)^2) / (1 - x + x^4 + x^5 + x^6). - Ilya Gutkovskiy, Jul 20 2021
MAPLE
a:= proc(n) option remember;
`if`(n=0, 1, a(n-1) +add(a(k)*a(n-4-k), k=3..n-4))
end:
seq(a(n), n=0..50); # Alois P. Heinz, May 07 2011
MATHEMATICA
Clear[ a ]; a[ 0 ]=1; a[ n_Integer ] := a[ n ]=a[ n-1 ]+Sum[ a[ k ]*a[ n-4-k ], {k, 3, n-4} ];
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
STATUS
approved