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 | 31 |
| 2 | 161 |
| 3 | 837 |
| 4 | 4357 |
| 5 | 22710 |
| 6 | 118530 |
| 7 | 619490 |
| 8 | 3242265 |
| 9 | 16993552 |
| 10 | 89197862 |
| 11 | 468891563 |
| 12 | 2468601733 |
| 13 | 13016765331 |
| 14 | 68745010766 |
| 15 | 363645146551 |
| 16 | 1926748983131 |
| 17 | 10225750976768 |
| 18 | 54362543336048 |
| 19 | 289501143028324 |
| 20 | 1544393456553619 |