# A137524 (b-file synthesized from sequence entry) 1 2 2 -3 3 6 4 4 5 -24 6 24 7 0 8 60 9 -180 10 120 11 -24 12 0 13 720 14 -1440 15 720 16 0 17 -840 18 0 19 8400 20 -12600 21 5040 22 960 23 0 24 -20160 25 0 26 100800 27 -120960 28 40320 29 0 30 60480 31 0 32 -423360 33 0 34 1270080 35 -1270080 36 362880 37 -120960 38 0 39 2419200 40 0 41 -8467200 42 0 43 16934400 44 -14515200 45 3628800 46 0 47 -11975040 48 0 49 79833600 50 0 51 -167650560 52 0