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 | 21 |
| 3 | 169 |
| 4 | 1515 |
| 5 | 13629 |
| 6 | 122641 |
| 7 | 1103763 |
| 8 | 9933861 |
| 9 | 89404729 |
| 10 | 804642555 |
| 11 | 7241782989 |
| 12 | 65176046881 |
| 13 | 586584421923 |
| 14 | 5279259797301 |
| 15 | 47513338175689 |
| 16 | 427620043581195 |
| 17 | 3848580392230749 |
| 18 | 34637223530076721 |
| 19 | 311735011770690483 |