# A007214 (b-file synthesized from sequence entry) 0 1 1 0 2 3 3 2 4 12 5 24 6 80 7 222 8 687 9 2096 10 6585 11 20892 12 67216 13 218412 14 716304 15 2367696 16 7881381 17 26398728 18 88918451 19 301014786 20 1023681792 21 3495786472 22 11983194420 23 41220422022 24 142247592803 25 492339048156 26 1708741395441 27 5945617039980 28 20737219258440 29 72488490389592