6487717237domain: NAppears in sequencesExpansion of e.g.f. exp(x) / (1 - x^3).at n=13A330044a(n) = (3*n+1)! * Sum_{k=0..n} 1 / (3*k+1)!.at n=4A337725a(n) = n! * Sum_{k=0..floor((n-1)/3)} 1 / (3*k+1)!.at n=13A349088