# A000440 (b-file synthesized from sequence entry) 4 9 5 30 6 180 7 980 8 8326 9 70272 10 695690 11 7518720 12 89193276 13 1148241458 14 15947668065 15 237613988040 16 3780133322620 17 63945806121448 18 1146081593303784 19 21693271558730304 20 432411684714253605 21 9053476937543082240 22 198641103956454088919