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| n | a(n) |
|---|---|
| 8 | 1 |
| 9 | 18 |
| 10 | 189 |
| 11 | 1518 |
| 12 | 10350 |
| 13 | 63180 |
| 14 | 356265 |
| 15 | 1893294 |
| 16 | 9612108 |
| 17 | 47071640 |
| 18 | 223926516 |
| 19 | 1040310648 |
| 20 | 4739192952 |
| 21 | 21238169904 |
| 22 | 93865125915 |
| 23 | 409972529754 |
| 24 | 1772528290407 |
| 25 | 7596549816030 |
| 26 | 32308782859535 |
| 27 | 136496564854650 |
| 28 | 573285572389530 |
| 29 | 2395339717603140 |
| 30 | 9962435643667605 |
[1,18,189,1518,10350,63180,356265,1893294,9612108, 47071640,223926516,1040310648,4739192952, 21238169904,93865125915,409972529754, 1772528290407,7596549816030,32308782859535, 136496564854650,573285572389530,2395339717603140, 9962435643667605] |