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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 4 |
| 3 | 13 |
| 4 | 25 |
| 5 | 77 |
| 6 | 161 |
| 7 | 393 |
| 8 | 726 |
| 9 | 2010 |
| 10 | 3850 |
| 11 | 7874 |
| 12 | 16791 |
| 13 | 31627 |
| 14 | 69695 |
| 15 | 139560 |
| 16 | 255997 |
| 17 | 482277 |
| 18 | 986021 |
| 19 | 1716430 |
| 20 | 3544299 |
| 21 | 6507128 |
| 22 | 11887340 |
| 23 | 21137849 |
| 24 | 38636535 |
| 25 | 70598032 |
| 26 | 123697772 |
| 27 | 233003286 |
| 28 | 412142276 |
| 29 | 711896765 |
| 30 | 1252360770 |
[1,1,4,13,25,77,161,393,726,2010,3850,7874,16791, 31627,69695,139560,255997,482277,986021,1716430, 3544299,6507128,11887340,21137849,38636535, 70598032,123697772,233003286,412142276,711896765, 1252360770] |