# A012353 (b-file synthesized from sequence entry) 0 0 1 0 2 2 3 -3 4 16 5 -50 6 440 7 -2856 8 30896 9 -291528 10 3760768 11 -47794120 12 742773920 13 -11810509776 14 214335913584 15 -4059112319640 16 84773616869376 17 -1860974227719872 18 44081861972926464 19 -1097880401356246656 20 29109695232734355712 21 -810074412297240074880