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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 0 |
| 2 | 0 |
| 3 | 1 |
| 4 | 6 |
| 5 | 26 |
| 6 | 101 |
| 7 | 376 |
| 8 | 1377 |
| 9 | 5017 |
| 10 | 18277 |
| 11 | 66727 |
| 12 | 244377 |
| 13 | 898129 |
| 14 | 3312554 |
| 15 | 12260129 |
| 16 | 45526754 |
| 17 | 169588754 |
| 18 | 633580634 |
| 19 | 2373550184 |
| 20 | 8914719134 |
| 21 | 33562602134 |
| 22 | 126640791884 |
| 23 | 478848661898 |
| 24 | 1814142235028 |
| 25 | 6885560250148 |
[0,0,0,1,6,26,101,376,1377,5017,18277,66727, 244377,898129,3312554,12260129,45526754,169588754, 633580634,2373550184,8914719134,33562602134, 126640791884,478848661898,1814142235028, 6885560250148] |