# A069563 (b-file synthesized from sequence entry) 1 1 2 4 3 9 4 28 5 85 6 426 7 3409 8 23864 9 167049 10 1837540 11 18375401 12 128627808 13 1157650273 14 10418852458 15 83350819665 16 1250262294976 17 22504721309569 18 382580262262674 19 4973543409414763 20 64656064322391920