# A152394 (b-file synthesized from sequence entry) 0 1 1 3 2 8 3 40 4 216 5 1386 6 9552 7 71820 8 571440 9 4815778 10 42465144 11 391058720 12 3738272328 13 37015339410 14 378307524768 15 3983307781956 16 43109512918560 17 478808036794306 18 5448659044584680 19 63446989372749528 20 755057167559816440