# A013333 (b-file synthesized from sequence entry)
0 0
1 1
2 0
3 2
4 -4
5 12
6 -120
7 128
8 -4464
9 6912
10 -206880
11 776800
12 -12788224
13 95713984
14 -1101528064
15 13091780224
16 -133871961344
17 2061579919104
18 -22144979338752
19 381671021731840
20 -4690276122840064
21 83860033272100864