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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 12 |
| 2 | 68 |
| 3 | 264 |
| 4 | 810 |
| 5 | 2112 |
| 6 | 4884 |
| 7 | 10296 |
| 8 | 20163 |
| 9 | 37180 |
| 10 | 65208 |
| 11 | 109616 |
| 12 | 177684 |
| 13 | 279072 |
| 14 | 426360 |
| 15 | 635664 |
| 16 | 927333 |
| 17 | 1326732 |
| 18 | 1865116 |
| 19 | 2580600 |
| 20 | 3519230 |
| 21 | 4736160 |
| 22 | 6296940 |
| 23 | 8278920 |
| 24 | 10772775 |
| 25 | 13884156 |
| 26 | 17735472 |
| 27 | 22467808 |
| 28 | 28242984 |
| 29 | 35245760 |
[1,12,68,264,810,2112,4884,10296,20163,37180, 65208,109616,177684,279072,426360,635664,927333, 1326732,1865116,2580600,3519230,4736160,6296940, 8278920,10772775,13884156,17735472,22467808, 28242984,35245760] |