# A063888 (b-file synthesized from sequence entry) 0 1 1 6 2 30 3 180 4 1026 5 6156 6 35940 7 215640 8 1271106 9 7626636 10 45182124 11 271092744 12 1610875836 13 9665255016 14 57546367704 15 345278206224 16 2058613385346 17 12351680312076 18 73717606430364 19 442305638582184 20 2641804748619732