# A012355 (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 3518848 11 -41141320 12 556495520 13 -7659162576 14 116623578864 15 -1844238858840 16 31500762034176 17 -562615136891072 18 10696734155925504 19 -212805382639718016 20 4464074777217786112 21 -97816050420003646080