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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 4 |
| 3 | 21 |
| 4 | 25 |
| 5 | 71 |
| 6 | 522 |
| 7 | 593 |
| 8 | 11789 |
| 9 | 12382 |
| 10 | 98463 |
| 11 | 209308 |
| 12 | 307771 |
| 13 | 1748163 |
| 14 | 5552260 |
| 15 | 7300423 |
| 16 | 297569180 |
| 17 | 304869603 |
| 18 | 1212177989 |
| 19 | 6365759548 |
| 20 | 7577937537 |
| 21 | 21521634622 |
| 22 | 158229379891 |
| 23 | 179751014513 |
| 24 | 3573498655638 |
| 25 | 3753249670151 |
| 26 | 29846246346695 |
| 27 | 63445742363541 |
[1,1,4,21,25,71,522,593,11789,12382,98463,209308, 307771,1748163,5552260,7300423,297569180, 304869603,1212177989,6365759548,7577937537, 21521634622,158229379891,179751014513, 3573498655638,3753249670151,29846246346695, 63445742363541] |