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| n | a(n) |
|---|---|
| 1 | 2 |
| 2 | 5 |
| 3 | 13 |
| 4 | 44 |
| 5 | 168 |
| 6 | 717 |
| 7 | 3360 |
| 8 | 17092 |
| 9 | 93538 |
| 10 | 546873 |
| 11 | 3396379 |
| 12 | 22300885 |
| 13 | 154193327 |
| 14 | 1118804486 |
| 15 | 8493592723 |
| 16 | 67288261914 |
| 17 | 554996479921 |
| 18 | 4756036642107 |
| 19 | 42266543239132 |
| 20 | 388879705390976 |
| 21 | 3698606881082199 |
| 22 | 36312877059583874 |
[2,5,13,44,168,717,3360,17092,93538,546873, 3396379,22300885,154193327,1118804486,8493592723, 67288261914,554996479921,4756036642107, 42266543239132,388879705390976,3698606881082199, 36312877059583874] |