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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 21 |
| 5 | 84 |
| 6 | 387 |
| 7 | 1953 |
| 8 | 10802 |
| 9 | 64267 |
| 10 | 408489 |
| 11 | 2750686 |
| 12 | 19518841 |
| 13 | 145236878 |
| 14 | 1128884559 |
| 15 | 9135566309 |
| 16 | 76758391212 |
| 17 | 667993213393 |
| 18 | 6008434514996 |
| 19 | 55755719348210 |
| 20 | 532896254763646 |
| 21 | 5238211003916685 |
| 22 | 52885470406233727 |
| 23 | 547751388283907208 |
| 24 | 5813693205313803535 |
| 25 | 63170000832869927871 |
[1,1,2,6,21,84,387,1953,10802,64267,408489, 2750686,19518841,145236878,1128884559,9135566309, 76758391212,667993213393,6008434514996, 55755719348210,532896254763646,5238211003916685, 52885470406233727,547751388283907208, 5813693205313803535,63170000832869927871] |