# A121676 (b-file synthesized from sequence entry) 0 1 1 2 2 6 3 32 4 250 5 2412 6 27524 7 360600 8 5296050 9 85805420 10 1515794467 11 28926900312 12 591903009295 13 12907255696636 14 298428274844730 15 7284351640977920 16 187013495992710210 17 5033669346061547724 18 141643700005223732471