# A158761 (b-file synthesized from sequence entry) 0 1 1 4 2 16 3 68 4 272 5 1092 6 4624 7 18500 8 74512 9 314436 10 1258512 11 5083204 12 21382416 13 85627972 14 346707472 15 1454102596 16 5826897680 17 23643380804 18 98889463824 19 396564832324 20 1612065835280 21 6725490517060 22 26992215104016