# A143555 (b-file synthesized from sequence entry) 0 1 1 1 2 4 3 8 4 28 5 80 6 308 7 984 8 3980 9 13472 10 56164 11 197032 12 838396 13 3013872 14 13015188 15 47624568 16 207971436 17 771336512 18 3397886660 19 12736715592 20 56502898140 21 213618833808 22 953139545076 23 3629043226392 24 16270547827020 25 62317467147744