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 | 0 |
| 2 | 1 |
| 3 | 5 |
| 4 | 23 |
| 5 | 99 |
| 6 | 433 |
| 7 | 1880 |
| 8 | 8238 |
| 9 | 36202 |
| 10 | 159898 |
| 11 | 708517 |
| 12 | 3150128 |
| 13 | 14042620 |
| 14 | 62751693 |
| 15 | 280997846 |
| 16 | 1260635337 |
| 17 | 5664870696 |
| 18 | 25493707908 |
| 19 | 114882350739 |
| 20 | 518318733052 |
| 21 | 2341079272919 |
| 22 | 10584488664085 |
| 23 | 47898510357544 |
| 24 | 216940538748652 |
| 25 | 983326680302665 |
| 26 | 4460343301915203 |