112555domain: NAppears in sequencesa(n) = -a(n-1) - a(n-2) + a(n-3), a(0)=3, a(1)=-1, a(2)=-1.at n=38A073145Expansion of (3 + 2*x + 3*x^2)/(1 + x + 3*x^2 - x^3).at n=19A073496a(n) = 74*n^2 + 1.at n=39A158742