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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 7 |
| 2 | 21 |
| 3 | 95 |
| 4 | 333 |
| 5 | 1319 |
| 6 | 4837 |
| 7 | 18447 |
| 8 | 68733 |
| 9 | 259447 |
| 10 | 972565 |
| 11 | 3661535 |
| 12 | 13756333 |
| 13 | 51754567 |
| 14 | 194586181 |
| 15 | 731919279 |
| 16 | 2752461533 |
| 17 | 10352254743 |
| 18 | 38932913525 |
| 19 | 146424889471 |
| 20 | 550683608589 |
| 21 | 2071066796007 |
| 22 | 7789015542949 |
| 23 | 29293584500047 |
| 24 | 110169505843517 |
| 25 | 414334209685687 |
[1,7,21,95,333,1319,4837,18447,68733,259447, 972565,3661535,13756333,51754567,194586181, 731919279,2752461533,10352254743,38932913525, 146424889471,550683608589,2071066796007, 7789015542949,29293584500047,110169505843517, 414334209685687] |