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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 2 |
| 3 | 4 |
| 4 | 6 |
| 5 | 10 |
| 6 | 60 |
| 7 | 66 |
| 8 | 100 |
| 9 | 144 |
| 10 | 156 |
| 11 | 450 |
| 12 | 454 |
| 13 | 456 |
| 14 | 744 |
| 15 | 1354 |
| 16 | 1942 |
| 17 | 2074 |
| 18 | 2556 |
| 19 | 3252 |
| 20 | 4300 |
| 21 | 9148 |
| 22 | 10318 |
| 23 | 10806 |
| 24 | 19518 |
| 25 | 26182 |
| 26 | 83580 |
[0,2,4,6,10,60,66,100,144,156,450,454,456,744, 1354,1942,2074,2556,3252,4300,9148,10318,10806, 19518,26182,83580] |