n | a(n) |
---|---|
0 | 1 |
1 | 0 |
2 | 1 |
3 | 4 |
4 | 18 |
5 | 80 |
6 | 357 |
7 | 1596 |
8 | 7150 |
9 | 32096 |
10 | 144362 |
11 | 650568 |
12 | 2937316 |
13 | 13286368 |
14 | 60205805 |
15 | 273290988 |
16 | 1242639446 |
17 | 5659468736 |
18 | 25816338046 |
19 | 117945079736 |
20 | 539646216188 |
21 | 2472638868960 |
22 | 11345220210658 |
23 | 52124831171544 |
24 | 239792244636876 |
25 | 1104495824173376 |
[1,0,1,4,18,80,357,1596,7150,32096,144362,650568, 2937316,13286368,60205805,273290988,1242639446, 5659468736,25816338046,117945079736,539646216188, 2472638868960,11345220210658,52124831171544, 239792244636876,1104495824173376] |