# A149839 (b-file synthesized from sequence entry) 0 1 1 2 2 4 3 12 4 36 5 105 6 359 7 1206 8 4067 9 14822 10 52823 11 192009 12 724475 13 2688197 14 10212299 15 39371249 16 150595178 17 587964607 18 2302876044 19 9017714047 20 35830596795 21 142208608418 22 566950728006 23 2279733680236 24 9155169681193 25 36992776831504 26 150085692169723 27 609053481684281 28 2485541205785126