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 | 4 |
| 1 | 5 |
| 2 | 43 |
| 3 | 263 |
| 4 | 1699 |
| 5 | 10895 |
| 6 | 69943 |
| 7 | 448943 |
| 8 | 2881699 |
| 9 | 18497135 |
| 10 | 118730023 |
| 11 | 762108143 |
| 12 | 4891844659 |
| 13 | 31399932335 |
| 14 | 201550911703 |
| 15 | 1293721577903 |
| 16 | 8304182337859 |
| 17 | 53303156937455 |
| 18 | 342144045482503 |
| 19 | 2196165379031663 |
| 20 | 14096818096762579 |
| 21 | 90485116626705455 |
| 22 | 580808823292457143 |