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 | 4 |
| 2 | 17 |
| 3 | 73 |
| 4 | 312 |
| 5 | 1333 |
| 6 | 5697 |
| 7 | 24348 |
| 8 | 104057 |
| 9 | 444713 |
| 10 | 1900592 |
| 11 | 8122653 |
| 12 | 34714177 |
| 13 | 148359668 |
| 14 | 634051937 |
| 15 | 2709778633 |
| 16 | 11580912872 |
| 17 | 49493911173 |
| 18 | 211524537857 |
| 19 | 904002715788 |
| 20 | 3863480419017 |
| 21 | 16511544365353 |
| 22 | 70566191040352 |