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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 11 |
| 4 | 73 |
| 5 | 707 |
| 6 | 8547 |
| 7 | 127379 |
| 8 | 2237804 |
| 9 | 45511484 |
| 10 | 1049155214 |
| 11 | 27060763974 |
| 12 | 771662014455 |
| 13 | 24109614539775 |
| 14 | 818906748562249 |
| 15 | 30044648617150066 |
| 16 | 1184045057676213763 |
| 17 | 49883902402848781573 |
| 18 | 2237286132689496359239 |
| 19 | 106426356238092171308928 |
| 20 | 5352031894869594850387969 |
[1,1,2,11,73,707,8547,127379,2237804,45511484, 1049155214,27060763974,771662014455, 24109614539775,818906748562249,30044648617150066, 1184045057676213763,49883902402848781573, 2237286132689496359239,106426356238092171308928, 5352031894869594850387969] |