158137domain: NAppears in sequencesNumber of ways to write n as an ordered sum of 1s, 2s, 3s and 4s such that no 2 precedes any 1 and no 3 precedes any 1 or 2.at n=32A123569G.f.: [ Sum_{n>=0} x^n * (1+x)^(n^2) ] * [ Sum_{n>=0} x^n / (1+x)^(n^2) ].at n=10A320950Expansion of (-1 + Product_{k>=1} 1 / (1 - x^k))^4.at n=12A341222