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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 5 |
| 3 | 19 |
| 4 | 79 |
| 5 | 372 |
| 6 | 1947 |
| 7 | 11177 |
| 8 | 69705 |
| 9 | 468429 |
| 10 | 3369363 |
| 11 | 25796583 |
| 12 | 209239154 |
| 13 | 1790741544 |
| 14 | 16114087300 |
| 15 | 151993139245 |
| 16 | 1498673357622 |
| 17 | 15410094488805 |
| 18 | 164884814714349 |
| 19 | 1832270712038289 |
| 20 | 21109130822778032 |
| 21 | 251727974604724389 |
[1,1,5,19,79,372,1947,11177,69705,468429,3369363, 25796583,209239154,1790741544,16114087300, 151993139245,1498673357622,15410094488805, 164884814714349,1832270712038289, 21109130822778032,251727974604724389] |