# A074417 (b-file synthesized from sequence entry) 1 1 2 1 3 2 4 5 5 25 6 104 7 450 8 1935 9 8666 10 39050 11 177784 12 814006 13 3756250 14 17437275 15 81380200 16 381468750 17 1795156250 18 8477078967 19 40154687500 20 190734843750 21 908261625600 22 4334883611534 23 20732050781250 24 99341072183730 25 476837158203125 26 2292486335637500