# A012931 (b-file synthesized from sequence entry) 0 0 1 2 2 -1 3 -12 4 42 5 172 6 -2250 7 896 8 153384 9 -952688 10 -11282040 11 209648736 12 279312528 13 -43286799008 14 318803909424 15 8375677890176 16 -180484941598080 17 -918969731775232 18 79664942329607808 19 -561407566293575168