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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 25 |
| 5 | 128 |
| 6 | 758 |
| 7 | 5014 |
| 8 | 36194 |
| 9 | 280433 |
| 10 | 2303918 |
| 11 | 19885534 |
| 12 | 179028087 |
| 13 | 1671644720 |
| 14 | 16114138846 |
| 15 | 159761516110 |
| 16 | 1623972412726 |
| 17 | 16880442523007 |
| 18 | 179026930243822 |
| 19 | 1933537655138482 |
| 20 | 21231023519199575 |
| 21 | 236674460790503286 |
| 22 | 2675162663681345170 |
| 23 | 30625903703241927542 |
[1,2,6,25,128,758,5014,36194,280433,2303918, 19885534,179028087,1671644720,16114138846, 159761516110,1623972412726,16880442523007, 179026930243822,1933537655138482, 21231023519199575,236674460790503286, 2675162663681345170,30625903703241927542] |