a(n) = (3*n+2)! * Sum_{k=0..n} 1 / (3*k+2)!.A337726a(n) = (3*n+2)! * Sum_{k=0..n} 1 / (3*k+2)!.Terms a(0) =1a(1) =61a(2) =20497a(3) =20292031a(4) =44317795705External referencesoeis: A337726