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| n | a(n) |
|---|---|
| 2 | 1 |
| 3 | 11 |
| 4 | 72 |
| 5 | 367 |
| 6 | 1630 |
| 7 | 6680 |
| 8 | 26082 |
| 9 | 98870 |
| 10 | 368045 |
| 11 | 1354850 |
| 12 | 4953503 |
| 13 | 18035279 |
| 14 | 65499031 |
| 15 | 237511321 |
| 16 | 860471110 |
| 17 | 3115667369 |
| 18 | 11277816388 |
| 19 | 40814611818 |
| 20 | 147692103728 |
| 21 | 534404499040 |
| 22 | 1933597628291 |
| 23 | 6996040095316 |
| 24 | 25312367524557 |
| 25 | 91581960107817 |
| 26 | 331348634005165 |
[1,11,72,367,1630,6680,26082,98870,368045,1354850, 4953503,18035279,65499031,237511321,860471110, 3115667369,11277816388,40814611818,147692103728, 534404499040,1933597628291,6996040095316, 25312367524557,91581960107817,331348634005165] |