# A045740 (b-file synthesized from sequence entry) 1 1 2 3 3 12 4 62 5 370 6 2397 7 16345 8 115376 9 834786 10 6152285 11 45990120 12 347673108 13 2652283517 14 20385035972 15 157656007680 16 1225743120520 17 9572972899946 18 75056029550721 19 590469939950716 20 4659115833115680 21 36859770507695688