A025253 a(n) = a(1)*a(n-1) + a(2)*a(n-2) + ...+ a(n-3)*a(3) for n >= 4.

0, 2, 1, 0, 2, 1, 4, 6, 10, 24, 36, 85, 152, 310, 638, 1232, 2620, 5194, 10840, 22332, 46004, 96528, 199816, 420365, 880112, 1851366, 3908854, 8245536, 17482220, 37049662, 78746776, 167602164, 357127116, 762506640, 1629288824, 3487128706, 7470956240