# A003202 (b-file synthesized from sequence entry) 0 1 1 6 2 18 3 48 4 126 5 300 6 750 7 1686 8 4074 9 8868 10 20892 11 44634 12 103392 13 216348 14 499908 15 1017780 16 2383596 17 4648470 18 11271102 19 20763036 20 52671018 21 91377918