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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | 4 |
| 4 | 13 |
| 5 | 88 |
| 6 | 493 |
| 7 | 4672 |
| 8 | 37369 |
| 9 | 454144 |
| 10 | 4732249 |
| 11 | 70084096 |
| 12 | 901188997 |
| 13 | 15728822272 |
| 14 | 240798388357 |
| 15 | 4836914249728 |
| 16 | 85948640603761 |
| 17 | 1952137912385536 |
| 18 | 39504564917358001 |
| 19 | 1000749157519458304 |
| 20 | 22726779729476308093 |
| 21 | 635146072839001735168 |
| 22 | 15998009117983994065693 |
| 23 | 488855521088102855606272 |
| 24 | 13526765851190230940840809 |
| 25 | 448599416591747486039670784 |
| 26 | 13528070218935445806530640649 |
[1,1,1,4,13,88,493,4672,37369,454144,4732249, 70084096,901188997,15728822272,240798388357, 4836914249728,85948640603761,1952137912385536, 39504564917358001,1000749157519458304, 22726779729476308093,635146072839001735168, 15998009117983994065693,488855521088102855606272, 13526765851190230940840809, 448599416591747486039670784, 13528070218935445806530640649] |