# A149578 (b-file synthesized from sequence entry) 0 1 1 1 2 5 3 15 4 51 5 211 6 795 7 3057 8 13001 9 52581 10 213253 11 925853 12 3879469 13 16223453 14 71442225 15 305928395 16 1305276203 17 5807259867 18 25240311855 19 109232894395 20 489780437147 21 2152075952175 22 9413280045751 23 42466522816087 24 188164257550383 25 829897208393779 26 3762535997730743 27 16782610498398015