# A073972 (b-file synthesized from sequence entry) 1 0 2 0 3 0 4 36 5 300 6 1440 7 7056 8 42336 9 272160 10 1700352 11 10349856 12 62099136 13 367960320 14 2173796352 15 12940881408 16 77716392192 17 468419708160 18 2821539889152 19 16960580969472 20 101763485816832 21 609985806796800 22 3656220357427200 23 21926115464435712 24 131556692786614272