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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 2 |
| 2 | 18 |
| 3 | 114 |
| 4 | 420 |
| 5 | 1170 |
| 6 | 2710 |
| 7 | 5538 |
| 8 | 10312 |
| 9 | 17890 |
| 10 | 29338 |
| 11 | 45970 |
| 12 | 69356 |
| 13 | 101362 |
| 14 | 144158 |
| 15 | 200258 |
| 16 | 272528 |
| 17 | 364226 |
| 18 | 479010 |
| 19 | 620978 |
| 20 | 794676 |
| 21 | 1005138 |
| 22 | 1257894 |
| 23 | 1559010 |
| 24 | 1915096 |
| 25 | 2333346 |
| 26 | 2821546 |
| 27 | 3388114 |
| 28 | 4042108 |
| 29 | 4793266 |
| 30 | 5652014 |
[0,2,18,114,420,1170,2710,5538,10312,17890,29338, 45970,69356,101362,144158,200258,272528,364226, 479010,620978,794676,1005138,1257894,1559010, 1915096,2333346,2821546,3388114,4042108,4793266, 5652014] |