# A149917 (b-file synthesized from sequence entry) 0 1 1 2 2 5 3 15 4 47 5 155 6 545 7 1982 8 7366 9 28040 10 108465 11 425789 12 1698808 13 6859370 14 27955680 15 114943633 16 476154065 17 1986712591 18 8348735338 19 35294521877 20 149972186973 21 640252876498 22 2745195496472 23 11820325855569 24 51102650867725 25 221726509972662 26 965121780389572 27 4213436370834023