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) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 3 |
| 4 | 13 |
| 5 | 68 |
| 6 | 401 |
| 7 | 2576 |
| 8 | 17670 |
| 9 | 127786 |
| 10 | 965890 |
| 11 | 7583944 |
| 12 | 61576198 |
| 13 | 515209694 |
| 14 | 4430434354 |
| 15 | 39073275005 |
| 16 | 352812956426 |
| 17 | 3257141096415 |
| 18 | 30708375193969 |
| 19 | 295384611397245 |
| 20 | 2896520002777988 |
| 21 | 28934822132722103 |
| 22 | 294279196616806638 |
| 23 | 3045540859482010041 |
| 24 | 32057787741226132890 |