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| n | a(n) |
|---|---|
| 1 | 3 |
| 2 | 157 |
| 3 | 1725 |
| 4 | 12318 |
| 5 | 71445 |
| 6 | 368408 |
| 7 | 1770697 |
| 8 | 8100180 |
| 9 | 35778250 |
| 10 | 153961577 |
| 11 | 648808393 |
| 12 | 2688490346 |
| 13 | 10985899831 |
| 14 | 44366461753 |
| 15 | 177379460528 |
| 16 | 703023818561 |
| 17 | 2765216924694 |
| 18 | 10803620128490 |
| 19 | 41957868667589 |
| 20 | 162081268856114 |
[3,157,1725,12318,71445,368408,1770697,8100180, 35778250,153961577,648808393,2688490346, 10985899831,44366461753,177379460528,703023818561, 2765216924694,10803620128490,41957868667589, 162081268856114] |