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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 6 |
| 2 | 24 |
| 3 | 100 |
| 4 | 396 |
| 5 | 1596 |
| 6 | 6364 |
| 7 | 25500 |
| 8 | 101916 |
| 9 | 407836 |
| 10 | 1631004 |
| 11 | 6524700 |
| 12 | 26097436 |
| 13 | 104392476 |
| 14 | 417564444 |
| 15 | 1670268700 |
| 16 | 6681052956 |
| 17 | 26724255516 |
| 18 | 106896934684 |
| 19 | 427587913500 |
| 20 | 1710351304476 |
| 21 | 6841405916956 |
| 22 | 27365622269724 |
| 23 | 109462491875100 |
| 24 | 437849961907996 |
| 25 | 1751399858816796 |
| 26 | 7005599412897564 |
| 27 | 28022397696329500 |
| 28 | 112089590695839516 |
[1,6,24,100,396,1596,6364,25500,101916,407836, 1631004,6524700,26097436,104392476,417564444, 1670268700,6681052956,26724255516,106896934684, 427587913500,1710351304476,6841405916956, 27365622269724,109462491875100,437849961907996, 1751399858816796,7005599412897564, 28022397696329500,112089590695839516] |