# A002272 (b-file synthesized from sequence entry) 0 1 1 0 2 0 3 261120 4 18947520 5 535818240 6 8320327680 7 83347937280 8 622558664640 9 3614759362560 10 17694184734720 11 73337844372480 12 272615629589760 13 898646461378560 14 2752654757806080 15 7687895624386560