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 | 7 |
| 2 | 33 |
| 3 | 151 |
| 4 | 705 |
| 5 | 3367 |
| 6 | 16353 |
| 7 | 80311 |
| 8 | 397185 |
| 9 | 1972807 |
| 10 | 9824673 |
| 11 | 49005271 |
| 12 | 244672065 |
| 13 | 1222297447 |
| 14 | 6108298593 |
| 15 | 30531927031 |
| 16 | 152630937345 |
| 17 | 763068593287 |
| 18 | 3815084686113 |
| 19 | 19074648589591 |
| 20 | 95370918425025 |
| 21 | 476847618556327 |