OFFSET
0,2
FORMULA
a(0) = 1; a(n) = (n-1)! * Sum_{i, j, k>=0 and i+j+k=n-1} (n-i) * (2^j+1) * (2^k+1) * a(i) * a(j) * a(k)/(i! * j! * k!).
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Jul 06 2025
STATUS
approved
