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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 5 |
| 3 | 25 |
| 4 | 137 |
| 5 | 801 |
| 6 | 4893 |
| 7 | 30857 |
| 8 | 199377 |
| 9 | 1313089 |
| 10 | 8782389 |
| 11 | 59491257 |
| 12 | 407308377 |
| 13 | 2814044897 |
| 14 | 19594237133 |
| 15 | 137364464681 |
| 16 | 968743846561 |
| 17 | 6868059398273 |
| 18 | 48921561805413 |
| 19 | 349942779608153 |
| 20 | 2512722402972457 |
| 21 | 18104571857859233 |
| 22 | 130856263145140861 |
| 23 | 948520413875412681 |
[1,1,5,25,137,801,4893,30857,199377,1313089, 8782389,59491257,407308377,2814044897,19594237133, 137364464681,968743846561,6868059398273, 48921561805413,349942779608153,2512722402972457, 18104571857859233,130856263145140861, 948520413875412681] |