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| n | a(n) |
|---|---|
| 1 | 3 |
| 2 | 15 |
| 3 | 75 |
| 4 | 363 |
| 5 | 1767 |
| 6 | 8463 |
| 7 | 40695 |
| 8 | 193983 |
| 9 | 926943 |
| 10 | 4404939 |
| 11 | 20967075 |
| 12 | 99421371 |
| 13 | 471987255 |
| 14 | 2234455839 |
| 15 | 10587573027 |
| 16 | 50060937987 |
| 17 | 236865126051 |
| 18 | 1118861842047 |
| 19 | 5288016609807 |
| 20 | 24958663919367 |
| 21 | 117855045251079 |
| 22 | 555890991721203 |
| 23 | 2622994107595707 |
[3,15,75,363,1767,8463,40695,193983,926943, 4404939,20967075,99421371,471987255,2234455839, 10587573027,50060937987,236865126051, 1118861842047,5288016609807,24958663919367, 117855045251079,555890991721203,2622994107595707] |