# A124026 (b-file synthesized from sequence entry) 1 0 2 2 3 1 4 14 5 26 6 132 7 364 8 1416 9 4488 10 16016 11 53296 12 184736 13 625184 14 2145600 15 7303360 16 24979584 17 85196928 18 291057920 19 993379072 20 3392317952 21 11580678656 22 39541748736 23 134998297600 24 460924372992 25 1573671536640 26 5372896120832