# A083727 (b-file synthesized from sequence entry) 0 0 1 -6 2 -8 3 0 4 32 5 120 6 336 7 840 8 1984 9 4536 10 10160 11 22440 12 49056 13 106392 14 229264 15 491400 16 1048448 17 2228088 18 4718448 19 9961320 20 20971360 21 44040024 22 92274512 23 192937800 24 402652992 25 838860600 26 1744830256 27 3623878440 28 7516192544 29 15569256216 30 32212254480 31 66571992840