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| n | a(n) |
|---|---|
| 1 | 4 |
| 2 | 6 |
| 3 | 20 |
| 4 | 30 |
| 5 | 60 |
| 6 | 270 |
| 7 | 630 |
| 8 | 728 |
| 9 | 1170 |
| 10 | 1638 |
| 11 | 1890 |
| 12 | 2310 |
| 13 | 2730 |
| 14 | 2970 |
| 15 | 4590 |
| 16 | 8190 |
| 17 | 8910 |
| 18 | 12870 |
| 19 | 14850 |
| 20 | 16830 |
| 21 | 17850 |
| 22 | 18018 |
| 23 | 18810 |
| 24 | 19110 |
| 25 | 19890 |
| 26 | 22230 |
| 27 | 27846 |
| 28 | 27930 |
| 29 | 33930 |
| 30 | 52290 |
| 31 | 56070 |
| 32 | 60512 |
| 33 | 61110 |
| 34 | 63630 |
| 35 | 64890 |
| 36 | 67410 |
| 37 | 68670 |
| 38 | 80730 |
| 39 | 86130 |
[4,6,20,30,60,270,630,728,1170,1638,1890,2310, 2730,2970,4590,8190,8910,12870,14850,16830,17850, 18018,18810,19110,19890,22230,27846,27930,33930, 52290,56070,60512,61110,63630,64890,67410,68670, 80730,86130] |