n | a(n) |
---|---|
0 | 1 |
1 | 4 |
2 | 20 |
3 | 132 |
4 | 1116 |
5 | 12420 |
6 | 171300 |
7 | 2884980 |
8 | 56674380 |
9 | 1289511300 |
10 | 34769949060 |
11 | 1063909626780 |
12 | 37255008811020 |
13 | 1470406699982220 |
14 | 63114539746598340 |
15 | 2936218980067393020 |
16 | 150241360192861037100 |
17 | 8497891914008911514100 |
18 | 514514062115556069627060 |
[1,4,20,132,1116,12420,171300,2884980,56674380, 1289511300,34769949060,1063909626780, 37255008811020,1470406699982220,63114539746598340, 2936218980067393020,150241360192861037100, 8497891914008911514100,514514062115556069627060] |