# A010580 (b-file synthesized from sequence entry) 0 1 1 12 2 132 3 1452 4 15852 5 173052 6 1884972 7 20532252 8 223437852 9 2431526492 10 26447593812 11 287669976492 12 3128064123732 13 34013987172972 14 369792173040492 15 4020299656610636 16 43702216875039660 17 475060467524653980 18 5163624600479230260 19 56125562454502452780 20 610010748386503122684