83683domain: NAppears in sequencesNumber of length n+3 0..6 arrays with every four consecutive terms having the sum of some three elements equal to three times the fourth.at n=19A248535G.f. satisfies A(x) = exp( Sum_{k>=1} (-1)^(k+1) * (3 + A(x^k)) * x^k/k ).at n=9A363509