182303186391domain: NAppears in sequencesa(0) = 1; for n > 0, a(n) = b(n) - n*b(n-1), b() = A076177().at n=25A092255Expansion of (1-x-2x^2+sqrt(1-2x-3x^2))/(2*(1-2x-3x^2)).at n=25A116410