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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 5 |
| 3 | 13 |
| 4 | 63 |
| 5 | 201 |
| 6 | 991 |
| 7 | 3543 |
| 8 | 17521 |
| 9 | 66375 |
| 10 | 329361 |
| 11 | 1299919 |
| 12 | 6461629 |
| 13 | 26223915 |
| 14 | 130525411 |
| 15 | 541026087 |
| 16 | 2695329199 |
| 17 | 11354835089 |
| 18 | 56607090975 |
| 19 | 241583878837 |
| 20 | 1204988720797 |
| 21 | 5197181851895 |
| 22 | 25933310360265 |
| 23 | 112838742024709 |
| 24 | 563231409876969 |
| 25 | 2468935733666465 |
| 26 | 12326783508725881 |
| 27 | 54379000362010723 |
[1,1,5,13,63,201,991,3543,17521,66375,329361, 1299919,6461629,26223915,130525411,541026087, 2695329199,11354835089,56607090975,241583878837, 1204988720797,5197181851895,25933310360265, 112838742024709,563231409876969,2468935733666465, 12326783508725881,54379000362010723] |