n | a(n) |
---|---|
0 | 0 |
1 | 1 |
2 | 4 |
3 | 15 |
4 | 56 |
5 | 209 |
6 | 780 |
7 | 2911 |
8 | 10864 |
9 | 40545 |
10 | 151316 |
11 | 564719 |
12 | 2107560 |
13 | 7865521 |
14 | 29354524 |
15 | 109552575 |
16 | 408855776 |
17 | 1525870529 |
18 | 5694626340 |
19 | 21252634831 |
20 | 79315912984 |
21 | 296011017105 |
22 | 1104728155436 |
23 | 4122901604639 |
24 | 15386878263120 |
25 | 57424611447841 |
26 | 214311567528244 |
[0,1,4,15,56,209,780,2911,10864,40545,151316, 564719,2107560,7865521,29354524,109552575, 408855776,1525870529,5694626340,21252634831, 79315912984,296011017105,1104728155436, 4122901604639,15386878263120,57424611447841, 214311567528244] |