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 | 11 |
| 5 | 43 |
| 6 | 183 |
| 7 | 813 |
| 8 | 3731 |
| 9 | 17563 |
| 10 | 84303 |
| 11 | 411093 |
| 12 | 2030833 |
| 13 | 10141953 |
| 14 | 51117801 |
| 15 | 259695379 |
| 16 | 1328454221 |
| 17 | 6836777765 |
| 18 | 35373248213 |
| 19 | 183892104895 |
| 20 | 960066929119 |
| 21 | 5031617143079 |
| 22 | 26462109374051 |
| 23 | 139609962072913 |
| 24 | 738695107457919 |