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 | 2 |
| 1 | 9 |
| 2 | 53 |
| 3 | 351 |
| 4 | 2417 |
| 5 | 16839 |
| 6 | 117713 |
| 7 | 823671 |
| 8 | 5765057 |
| 9 | 40354119 |
| 10 | 282476273 |
| 11 | 1977328791 |
| 12 | 13841291297 |
| 13 | 96889018599 |
| 14 | 678223089233 |
| 15 | 4747561542711 |
| 16 | 33232930635137 |
| 17 | 232630514118279 |
| 18 | 1628413598172593 |
| 19 | 11398895185897431 |