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| n | a(n) |
|---|---|
| 1 | 2 |
| 2 | 6 |
| 3 | 19 |
| 4 | 62 |
| 5 | 207 |
| 6 | 705 |
| 7 | 2445 |
| 8 | 8622 |
| 9 | 30871 |
| 10 | 112061 |
| 11 | 411765 |
| 12 | 1529225 |
| 13 | 5731741 |
| 14 | 21652623 |
| 15 | 82341729 |
| 16 | 314889102 |
| 17 | 1209849831 |
| 18 | 4666707813 |
| 19 | 18060052389 |
| 20 | 70085525877 |
| 21 | 272615721621 |
| 22 | 1062509835063 |
| 23 | 4148096423409 |
| 24 | 16217945020377 |
| 25 | 63487732755357 |
| 26 | 248806555083495 |
[2,6,19,62,207,705,2445,8622,30871,112061,411765, 1529225,5731741,21652623,82341729,314889102, 1209849831,4666707813,18060052389,70085525877, 272615721621,1062509835063,4148096423409, 16217945020377,63487732755357,248806555083495] |