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| n | a(n) |
|---|---|
| 1 | 2 |
| 2 | 6 |
| 3 | 66 |
| 4 | 378 |
| 5 | 1190 |
| 6 | 1470 |
| 7 | 25806 |
| 8 | 58590 |
| 9 | 134946 |
| 10 | 137346 |
| 11 | 170586 |
| 12 | 272610 |
| 13 | 285390 |
| 14 | 420210 |
| 15 | 538734 |
| 16 | 592410 |
| 17 | 618450 |
| 18 | 680706 |
| 19 | 778806 |
| 20 | 1163066 |
| 21 | 1520442 |
| 22 | 1700946 |
| 23 | 2099202 |
| 24 | 2831010 |
| 25 | 4020030 |
| 26 | 4174170 |
| 27 | 4516110 |
| 28 | 5059890 |
| 29 | 5215770 |
[2,6,66,378,1190,1470,25806,58590,134946,137346, 170586,272610,285390,420210,538734,592410,618450, 680706,778806,1163066,1520442,1700946,2099202, 2831010,4020030,4174170,4516110,5059890,5215770] |