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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 5 |
| 3 | 17 |
| 4 | 60 |
| 5 | 226 |
| 6 | 894 |
| 7 | 3596 |
| 8 | 14733 |
| 9 | 61458 |
| 10 | 259481 |
| 11 | 1106753 |
| 12 | 4764856 |
| 13 | 20677287 |
| 14 | 90314950 |
| 15 | 396783369 |
| 16 | 1752566181 |
| 17 | 7776050081 |
| 18 | 34641886875 |
| 19 | 154916582579 |
| 20 | 695094294939 |
| 21 | 3128227114848 |
| 22 | 14118442677861 |
| 23 | 63883713196776 |
| 24 | 289742429602369 |
| 25 | 1317022255376015 |
| 26 | 5998719802774542 |
| 27 | 27374214721917542 |
[1,2,5,17,60,226,894,3596,14733,61458,259481, 1106753,4764856,20677287,90314950,396783369, 1752566181,7776050081,34641886875,154916582579, 695094294939,3128227114848,14118442677861, 63883713196776,289742429602369,1317022255376015, 5998719802774542,27374214721917542] |