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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 13 |
| 5 | 31 |
| 6 | 73 |
| 7 | 172 |
| 8 | 399 |
| 9 | 932 |
| 10 | 2177 |
| 11 | 5081 |
| 12 | 11853 |
| 13 | 27662 |
| 14 | 64554 |
| 15 | 150639 |
| 16 | 351520 |
| 17 | 820296 |
| 18 | 1914208 |
| 19 | 4466904 |
| 20 | 10423760 |
| 21 | 24324417 |
| 22 | 56762346 |
| 23 | 132458006 |
| 24 | 309097941 |
| 25 | 721296815 |
| 26 | 1683185225 |
| 27 | 3927803988 |
| 28 | 9165743599 |
| 29 | 21388759708 |
| 30 | 49911830577 |
[1,2,6,13,31,73,172,399,932,2177,5081,11853,27662, 64554,150639,351520,820296,1914208,4466904, 10423760,24324417,56762346,132458006,309097941, 721296815,1683185225,3927803988,9165743599, 21388759708,49911830577] |