# A034620 (b-file synthesized from sequence entry) 0 1 1 0 2 540 3 21120 4 286740 5 2132352 6 10878300 7 44012160 8 146719620 9 417436800 10 1093070376 11 2572283520 12 5570541780 13 11568510720 14 22583167200 15 41422741632 16 75113550180 17 129368897280 18 214148621340