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| n | a(n) |
|---|---|
| 1 | 4 |
| 2 | 25 |
| 3 | 31 |
| 4 | 72 |
| 5 | 170 |
| 6 | 382 |
| 7 | 873 |
| 8 | 2013 |
| 9 | 4618 |
| 10 | 10598 |
| 11 | 24347 |
| 12 | 55915 |
| 13 | 128406 |
| 14 | 294906 |
| 15 | 677293 |
| 16 | 1555481 |
| 17 | 3572366 |
| 18 | 8204410 |
| 19 | 18842487 |
| 20 | 43274223 |
| 21 | 99384898 |
| 22 | 228250358 |
| 23 | 524206673 |
| 24 | 1203908917 |
| 25 | 2764933650 |
| 26 | 6350030286 |
| 27 | 14583671731 |
| 28 | 33493301843 |
| 29 | 76921730606 |
[4,25,31,72,170,382,873,2013,4618,10598,24347, 55915,128406,294906,677293,1555481,3572366, 8204410,18842487,43274223,99384898,228250358, 524206673,1203908917,2764933650,6350030286, 14583671731,33493301843,76921730606] |