# A225524 (b-file synthesized from sequence entry) 0 1 1 2 2 8 3 24 4 66 5 184 6 488 7 1248 8 3136 9 7776 10 18780 11 44880 12 105896 13 246124 14 567008 15 1293840 16 2920626 17 6545352 18 14555388 19 32115120 20 70421792 21 153451488 22 332314512 23 715843200 24 1534016392 25 3270661294 26 6941489040 27 14667591672 28 30859685088 29 64670865304 30 135011595856 31 280813639680