# A004537 (b-file synthesized from sequence entry) 0 1 1 0 2 0 3 4600 4 93150 5 953856 6 6476800 7 32788800 8 133204500 9 458086400 10 1384998912 11 3771829800 12 9403968600 13 21771763200 14 47406643200 15 97917423808 16 192825064350 17 364086835200 18 663509299200 19 1171711866600