A049139 Revert transform of (1 - x - 2x^2 + x^3)/(1 - 2x^2).

1, 1, 2, 6, 20, 72, 272, 1063, 4262, 17432, 72448, 305074, 1298812, 5581188, 24175560, 105448157, 462745106, 2041634108, 9050879192, 40296196096, 180099939464, 807757872276, 3634378951656, 16399912908504, 74201196229816