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| n | a(n) |
|---|---|
| 0 | 20 |
| 1 | 140 |
| 2 | 560 |
| 3 | 1680 |
| 4 | 4200 |
| 5 | 9240 |
| 6 | 18480 |
| 7 | 34320 |
| 8 | 60060 |
| 9 | 100100 |
| 10 | 160160 |
| 11 | 247520 |
| 12 | 371280 |
| 13 | 542640 |
| 14 | 775200 |
| 15 | 1085280 |
| 16 | 1492260 |
| 17 | 2018940 |
| 18 | 2691920 |
| 19 | 3542000 |
| 20 | 4604600 |
| 21 | 5920200 |
| 22 | 7534800 |
| 23 | 9500400 |
| 24 | 11875500 |
| 25 | 14725620 |
[20,140,560,1680,4200,9240,18480,34320,60060, 100100,160160,247520,371280,542640,775200,1085280, 1492260,2018940,2691920,3542000,4604600,5920200, 7534800,9500400,11875500,14725620] |