URL: https://oeis.org/A218385/b218385.txt
# A218385 (b-file synthesized from sequence entry)
1 4
2 90
3 560
4 4032
5 302400
6 34214400
7 415134720
8 5448643200
9 1162377216000
10 320118685286400
11 5792623828992000
12 110586454917120000
13 46833363657400320000
14 1034080669555399065600
15 23863400066663055360000
16 574489260864110592000000
17 14403266468807344128000000
18 10162944820390462016716800000
