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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 2 |
| 2 | 14 |
| 3 | 62 |
| 4 | 242 |
| 5 | 912 |
| 6 | 3418 |
| 7 | 12854 |
| 8 | 48602 |
| 9 | 184736 |
| 10 | 705410 |
| 11 | 2704132 |
| 12 | 10400574 |
| 13 | 40116572 |
| 14 | 155117490 |
| 15 | 601080358 |
| 16 | 2333606186 |
| 17 | 9075135264 |
| 18 | 35345263762 |
| 19 | 137846528780 |
| 20 | 538257874398 |
| 21 | 2104098963676 |
| 22 | 8233430727554 |
| 23 | 32247603683052 |
| 24 | 126410606437702 |
| 25 | 495918532948052 |
| 26 | 1946939425648058 |
[0,2,14,62,242,912,3418,12854,48602,184736,705410, 2704132,10400574,40116572,155117490,601080358, 2333606186,9075135264,35345263762,137846528780, 538257874398,2104098963676,8233430727554, 32247603683052,126410606437702,495918532948052, 1946939425648058] |