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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 9 |
| 3 | 31 |
| 4 | 31 |
| 5 | 233 |
| 6 | 1112 |
| 7 | 4620 |
| 8 | 29589 |
| 9 | 169601 |
| 10 | 1004366 |
| 11 | 6170528 |
| 12 | 37097303 |
| 13 | 226884023 |
| 14 | 1384096579 |
| 15 | 8423128709 |
| 16 | 51431654299 |
| 17 | 313700623628 |
| 18 | 1913231218064 |
| 19 | 11674556253410 |
| 20 | 71220090528854 |
| 21 | 434503086638439 |
| 22 | 2650996753675544 |
[1,9,31,31,233,1112,4620,29589,169601,1004366, 6170528,37097303,226884023,1384096579,8423128709, 51431654299,313700623628,1913231218064, 11674556253410,71220090528854,434503086638439, 2650996753675544] |