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) |
|---|---|
| 0 | 1 |
| 1 | 9 |
| 2 | 61 |
| 3 | 369 |
| 4 | 2501 |
| 5 | 17259 |
| 6 | 120367 |
| 7 | 842739 |
| 8 | 5910189 |
| 9 | 41476599 |
| 10 | 291156071 |
| 11 | 2044081081 |
| 12 | 14351282807 |
| 13 | 100760813695 |
| 14 | 707450453645 |
| 15 | 4967087326989 |
| 16 | 34874511797933 |
| 17 | 244858234557953 |
| 18 | 1719180148930309 |
| 19 | 12070578961004535 |