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 | 2 |
| 2 | 4 |
| 3 | 9 |
| 4 | 22 |
| 5 | 58 |
| 6 | 163 |
| 7 | 478 |
| 8 | 1439 |
| 9 | 4415 |
| 10 | 13780 |
| 11 | 43757 |
| 12 | 141400 |
| 13 | 465016 |
| 14 | 1555961 |
| 15 | 5294885 |
| 16 | 18315089 |
| 17 | 64357854 |
| 18 | 229601019 |
| 19 | 831132731 |
| 20 | 3051030786 |
| 21 | 11351968321 |
| 22 | 42788503744 |
| 23 | 163309466037 |
| 24 | 630861836558 |
| 25 | 2465577001903 |
| 26 | 9745376900983 |