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| n | a(n) |
|---|---|
| 1 | 18 |
| 2 | 324 |
| 3 | 1504 |
| 4 | 4534 |
| 5 | 10898 |
| 6 | 22714 |
| 7 | 42874 |
| 8 | 75198 |
| 9 | 124602 |
| 10 | 197280 |
| 11 | 300900 |
| 12 | 444814 |
| 13 | 640282 |
| 14 | 900710 |
| 15 | 1241902 |
| 16 | 1682326 |
| 17 | 2243394 |
| 18 | 2949756 |
| 19 | 3829608 |
| 20 | 4915014 |
| 21 | 6242242 |
| 22 | 7852114 |
| 23 | 9790370 |
| 24 | 12108046 |
| 25 | 14861866 |
| 26 | 18114648 |
| 27 | 21935724 |
| 28 | 26401374 |
| 29 | 31595274 |
[18,324,1504,4534,10898,22714,42874,75198,124602, 197280,300900,444814,640282,900710,1241902, 1682326,2243394,2949756,3829608,4915014,6242242, 7852114,9790370,12108046,14861866,18114648, 21935724,26401374,31595274] |