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 | 3 |
| 2 | 9 |
| 3 | 31 |
| 4 | 115 |
| 5 | 447 |
| 6 | 1803 |
| 7 | 7499 |
| 8 | 32069 |
| 9 | 140795 |
| 10 | 633981 |
| 11 | 2925671 |
| 12 | 13826405 |
| 13 | 66861107 |
| 14 | 330544409 |
| 15 | 1669024071 |
| 16 | 8598951451 |
| 17 | 45160258503 |
| 18 | 241540648011 |
| 19 | 1314519420803 |
| 20 | 7273377034547 |
| 21 | 40886211572271 |
| 22 | 233344325395327 |