# A072674 (b-file synthesized from sequence entry) 0 0 1 4 2 14 3 40 4 110 5 304 6 854 7 2440 8 7070 9 20704 10 61094 11 181240 12 539630 13 1610704 14 4815734 15 14414440 16 43177790 17 129402304 18 387944774 19 1163310040 20 3488881550 21 10464547504 22 31389448214 23 94159956040 24 282463090910 25 847355718304