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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | 4 |
| 4 | 4 |
| 5 | 11 |
| 6 | 67 |
| 7 | 29 |
| 8 | 260 |
| 9 | 876 |
| 10 | 3841 |
| 11 | 34134 |
| 12 | 69774 |
| 13 | 152231 |
| 14 | 774243 |
| 15 | 4182754 |
| 16 | 30376720 |
| 17 | 409813561 |
| 18 | 1056300594 |
| 19 | 3175397668 |
| 20 | 3655126844 |
| 21 | 91668397027 |
| 22 | 499871922705 |
| 23 | 5219638765816 |
| 24 | 120716816247428 |
| 25 | 17518596045460 |
| 26 | 193032439198301 |
| 27 | 3860666483055372 |
| 28 | 22675538336311998 |
[1,1,1,4,4,11,67,29,260,876,3841,34134,69774, 152231,774243,4182754,30376720,409813561, 1056300594,3175397668,3655126844,91668397027, 499871922705,5219638765816,120716816247428, 17518596045460,193032439198301,3860666483055372, 22675538336311998] |