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 | 12 |
| 3 | 46 |
| 4 | 181 |
| 5 | 705 |
| 6 | 2757 |
| 7 | 10765 |
| 8 | 42058 |
| 9 | 164280 |
| 10 | 641739 |
| 11 | 2506789 |
| 12 | 9792253 |
| 13 | 38251227 |
| 14 | 149420064 |
| 15 | 583676434 |
| 16 | 2280003517 |
| 17 | 8906330973 |
| 18 | 34790619369 |
| 19 | 135901886149 |
| 20 | 530870766310 |