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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 13 |
| 3 | 23 |
| 4 | 141 |
| 5 | 615 |
| 6 | 2394 |
| 7 | 11752 |
| 8 | 56417 |
| 9 | 267220 |
| 10 | 1288938 |
| 11 | 6174598 |
| 12 | 29660929 |
| 13 | 142473501 |
| 14 | 684767996 |
| 15 | 3289838593 |
| 16 | 15810180948 |
| 17 | 75973685362 |
| 18 | 365101919123 |
| 19 | 1754526797629 |
| 20 | 8431612710548 |
| 21 | 40519184505939 |
| 22 | 194720508520524 |
[1,13,23,141,615,2394,11752,56417,267220,1288938, 6174598,29660929,142473501,684767996,3289838593, 15810180948,75973685362,365101919123, 1754526797629,8431612710548,40519184505939, 194720508520524] |