# A169797 (b-file synthesized from sequence entry) 0 1 1 10 2 65 3 340 4 1550 5 6412 6 24650 7 89440 8 309605 9 1030490 10 3317445 11 10377180 12 31655820 13 94451520 14 276313200 15 794169792 16 2246410560 17 6262748160 18 17230138880 19 46831339520 20 125870737408 21 334826700800 22 882159984640 23 2303540756480 24 5965195018240 25 15327324667904