# A183145 (b-file synthesized from sequence entry) 0 1 1 1 2 3 3 18 4 121 5 928 6 6240 7 46617 8 360997 9 2889223 10 23635458 11 195429765 12 1643489944 13 13988813548 14 120403750665 15 1045933596357 16 9158182856203 17 80773120032142 18 716955897008481 19 6400569497637804 20 57436282624514236