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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 15 |
| 3 | 78 |
| 4 | 411 |
| 5 | 2178 |
| 6 | 11574 |
| 7 | 61596 |
| 8 | 328083 |
| 9 | 1748346 |
| 10 | 9319650 |
| 11 | 49688004 |
| 12 | 264943902 |
| 13 | 1412826132 |
| 14 | 7534329804 |
| 15 | 40180417848 |
| 16 | 214285867011 |
| 17 | 1142822599722 |
| 18 | 6094924220394 |
| 19 | 32505784870068 |
| 20 | 173362418710506 |
| 21 | 924593002335612 |
| 22 | 4931138212856244 |
| 23 | 26299312319336328 |
| 24 | 140262655976846766 |
[1,3,15,78,411,2178,11574,61596,328083,1748346, 9319650,49688004,264943902,1412826132,7534329804, 40180417848,214285867011,1142822599722, 6094924220394,32505784870068,173362418710506, 924593002335612,4931138212856244, 26299312319336328,140262655976846766] |