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 | 2 |
| 2 | 5 |
| 3 | 20 |
| 4 | 85 |
| 5 | 418 |
| 6 | 2242 |
| 7 | 12828 |
| 8 | 77777 |
| 9 | 493286 |
| 10 | 3260485 |
| 11 | 22314484 |
| 12 | 157735801 |
| 13 | 1147285362 |
| 14 | 8570960234 |
| 15 | 65611620808 |
| 16 | 513963377327 |
| 17 | 4113363020482 |
| 18 | 33598074760393 |
| 19 | 279764563749076 |
| 20 | 2372822051513583 |
| 21 | 20481425601917742 |
| 22 | 179795508212739402 |
| 23 | 1604084463778300348 |
| 24 | 14536376462636666141 |