# A007334 (b-file synthesized from sequence entry) 2 1 3 2 4 8 5 50 6 432 7 4802 8 65536 9 1062882 10 20000000 11 428717762 12 10319560704 13 275716983698 14 8099130339328 15 259492675781250 16 9007199254740992 17 336755653118801858 18 13493281232954916864 19 576882827135242335362 20 26214400000000000000000