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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 18 |
| 3 | 19 |
| 4 | 48 |
| 5 | 175 |
| 6 | 508 |
| 7 | 1522 |
| 8 | 5065 |
| 9 | 16968 |
| 10 | 56041 |
| 11 | 187865 |
| 12 | 632318 |
| 13 | 2129542 |
| 14 | 7184550 |
| 15 | 24247946 |
| 16 | 81877297 |
| 17 | 276519444 |
| 18 | 934064187 |
| 19 | 3155663032 |
| 20 | 10661937499 |
| 21 | 36024652028 |
| 22 | 121723990676 |
| 23 | 411304232139 |
| 24 | 1389808116350 |
| 25 | 4696240793449 |
[1,18,19,48,175,508,1522,5065,16968,56041,187865, 632318,2129542,7184550,24247946,81877297, 276519444,934064187,3155663032,10661937499, 36024652028,121723990676,411304232139, 1389808116350,4696240793449] |