# A331334 (b-file synthesized from sequence entry) 0 1 1 0 2 -4 3 32 4 -240 5 1792 6 -11840 7 26112 8 1589504 9 -57548800 10 1556757504 11 -39250780160 12 973563695104 13 -24122607992832 14 596246557736960 15 -14477682566889472 16 332039052050104320 17 -6425352382711857152 18 53086817854485692416 19 4505005802471597015040 20 -419037805969718712991744