OFFSET
0,5
FORMULA
a(4*n) = 9^n for n >= 0.
a(n) = Sum_{k=0..floor(n/4)} 8^k * binomial(n/4,k).
a(n) == 1 (mod 2).
PROG
(PARI) a(n) = sum(k=0, n\4, 8^k*binomial(n/4, k));
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Jun 11 2024
STATUS
approved