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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 2 |
| 3 | 5 |
| 4 | 19 |
| 5 | 73 |
| 6 | 297 |
| 7 | 1256 |
| 8 | 5467 |
| 9 | 24368 |
| 10 | 110610 |
| 11 | 509715 |
| 12 | 2377978 |
| 13 | 11210451 |
| 14 | 53318599 |
| 15 | 255537199 |
| 16 | 1232866889 |
| 17 | 5982965779 |
| 18 | 29185293329 |
| 19 | 143026402189 |
| 20 | 703829126231 |
| 21 | 3476496240860 |
| 22 | 17230140895115 |
| 23 | 85659915381510 |
| 24 | 427065111704502 |
| 25 | 2134705956413458 |
[0,1,2,5,19,73,297,1256,5467,24368,110610,509715, 2377978,11210451,53318599,255537199,1232866889, 5982965779,29185293329,143026402189,703829126231, 3476496240860,17230140895115,85659915381510, 427065111704502,2134705956413458] |