# A037676 (b-file synthesized from sequence entry) 1 1 2 6 3 38 4 231 5 1387 6 8322 7 49934 8 299607 9 1797643 10 10785858 11 64715150 12 388290903 13 2329745419 14 13978472514 15 83870835086 16 503225010519 17 3019350063115 18 18116100378690 19 108696602272142 20 652179613632855 21 3913077681797131