# A006387 (b-file synthesized from sequence entry) 0 0 1 0 2 1 3 6 4 40 5 320 6 2946 7 29364 8 309558 9 3365108 10 37246245 11 416751008 12 4696232371 13 53186743416 14 604690121555 15 6896534910612 16 78867385697513 17 904046279771682 18 10384916465797240 19 119522063788612992 20 1378014272286250059