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| n | a(n) |
|---|---|
| 1 | 4 |
| 2 | 23 |
| 3 | 81 |
| 4 | 292 |
| 5 | 1096 |
| 6 | 4172 |
| 7 | 15953 |
| 8 | 61111 |
| 9 | 234288 |
| 10 | 898583 |
| 11 | 3447045 |
| 12 | 13224257 |
| 13 | 50735544 |
| 14 | 194653051 |
| 15 | 746816146 |
| 16 | 2865285427 |
| 17 | 10993168588 |
| 18 | 42177249636 |
| 19 | 161820597240 |
| 20 | 620853918472 |
| 21 | 2382018289657 |
| 22 | 9139044147504 |
| 23 | 35063597098216 |
[4,23,81,292,1096,4172,15953,61111,234288,898583, 3447045,13224257,50735544,194653051,746816146, 2865285427,10993168588,42177249636,161820597240, 620853918472,2382018289657,9139044147504, 35063597098216] |