# A004371 (b-file synthesized from sequence entry) 3 1 4 28 5 595 6 11480 7 211876 8 3819816 9 67945521 10 1198774720 11 21042072975 12 368136785016 13 6426898010533 14 112044912118048 15 1951641934005400 16 33976189889821200 17 591315394579074378 18 10289781864706066800