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 | 2 |
| 4 | 3 |
| 5 | 6 |
| 6 | 14 |
| 7 | 32 |
| 8 | 90 |
| 9 | 279 |
| 10 | 942 |
| 11 | 3468 |
| 12 | 13777 |
| 13 | 57747 |
| 14 | 254671 |
| 15 | 1170565 |
| 16 | 5580706 |
| 17 | 27487418 |
| 18 | 139477796 |
| 19 | 727458338 |
| 20 | 3893078684 |
| 21 | 21346838204 |
| 22 | 119787629215 |
| 23 | 687200870250 |