n | a(n) |
---|---|
1 | 0 |
2 | 0 |
3 | 0 |
4 | 1 |
5 | 4 |
6 | 16 |
7 | 64 |
8 | 252 |
9 | 1018 |
10 | 4182 |
11 | 17510 |
12 | 74510 |
13 | 322034 |
14 | 1410362 |
15 | 6251114 |
16 | 27998532 |
17 | 126583634 |
18 | 577079333 |
19 | 2650573354 |
20 | 12256481666 |
21 | 57021299394 |
22 | 266754944481 |
23 | 1254245360430 |
24 | 5924659521632 |
25 | 28105641930102 |
26 | 133853504339029 |
27 | 639801068848128 |
[0,0,0,1,4,16,64,252,1018,4182,17510,74510,322034, 1410362,6251114,27998532,126583634,577079333, 2650573354,12256481666,57021299394,266754944481, 1254245360430,5924659521632,28105641930102, 133853504339029,639801068848128] |