This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 9 |
| 3 | 49 |
| 4 | 289 |
| 5 | 1281 |
| 6 | 7041 |
| 7 | 28673 |
| 8 | 147969 |
| 9 | 602113 |
| 10 | 2951169 |
| 11 | 11534337 |
| 12 | 57876481 |
| 13 | 218103809 |
| 14 | 1056997377 |
| 15 | 4113563649 |
| 16 | 19394592769 |
| 17 | 73014444033 |
| 18 | 354385657857 |
| 19 | 1305670057985 |
| 20 | 6210524807169 |
| 21 | 23571585826817 |
| 22 | 108851659538433 |
| 23 | 404620279021569 |
| 24 | 1942025331015681 |