# A049139 (b-file synthesized from sequence entry) 1 1 2 1 3 2 4 6 5 20 6 72 7 272 8 1063 9 4262 10 17432 11 72448 12 305074 13 1298812 14 5581188 15 24175560 16 105448157 17 462745106 18 2041634108 19 9050879192 20 40296196096 21 180099939464 22 807757872276 23 3634378951656 24 16399912908504 25 74201196229816