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 | 11 |
| 3 | 47 |
| 4 | 219 |
| 5 | 1075 |
| 6 | 5459 |
| 7 | 28383 |
| 8 | 150131 |
| 9 | 804515 |
| 10 | 4355163 |
| 11 | 23768079 |
| 12 | 130572363 |
| 13 | 721247571 |
| 14 | 4002344355 |
| 15 | 22296869823 |
| 16 | 124633584099 |
| 17 | 698707769923 |
| 18 | 3927060020651 |
| 19 | 22121780745711 |
| 20 | 124865811262139 |
| 21 | 706065855417203 |
| 22 | 3998950848888051 |