119762domain: NAppears in sequencesa(n) = Sum{a(k): k=0,1,2,...,n-4,n-2,n-1}; a(n-3) is not a summand; initial terms are 2,2,3.at n=19A049873Coefficient of x^n in (3-sqrt(5+4*sqrt(1-36*x)))/12.at n=4A379809