# A203232 (b-file synthesized from sequence entry) 1 1 2 5 3 16 4 60 5 156 6 540 7 1296 8 4320 9 9936 10 32400 11 72576 12 233280 13 513216 14 1632960 15 3545856 16 11197440 17 24074496 18 75582720 19 161243136 20 503884800 21 1068235776 22 3325639680 23 7014076416 24 21767823360 25 45712429056 26 141490851840