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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 7 |
| 3 | 26 |
| 4 | 103 |
| 5 | 431 |
| 6 | 1855 |
| 7 | 8172 |
| 8 | 36617 |
| 9 | 166316 |
| 10 | 763682 |
| 11 | 3537557 |
| 12 | 16506691 |
| 13 | 77503471 |
| 14 | 365818093 |
| 15 | 1734513028 |
| 16 | 8256719514 |
| 17 | 39439734441 |
| 18 | 188966919172 |
| 19 | 907847268968 |
| 20 | 4372082095389 |
| 21 | 21101141433849 |
| 22 | 102040426087208 |
| 23 | 494319114044965 |
| 24 | 2398510207471090 |
| 25 | 11655029385099377 |
| 26 | 56711232690554604 |
| 27 | 276287353453444549 |
[1,2,7,26,103,431,1855,8172,36617,166316,763682, 3537557,16506691,77503471,365818093,1734513028, 8256719514,39439734441,188966919172,907847268968, 4372082095389,21101141433849,102040426087208, 494319114044965,2398510207471090, 11655029385099377,56711232690554604, 276287353453444549] |