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 | 13 |
| 3 | 55 |
| 4 | 229 |
| 5 | 943 |
| 6 | 3853 |
| 7 | 15655 |
| 8 | 63349 |
| 9 | 255583 |
| 10 | 1028893 |
| 11 | 4135255 |
| 12 | 16600069 |
| 13 | 66577423 |
| 14 | 266841133 |
| 15 | 1068958855 |
| 16 | 4280618389 |
| 17 | 17136822463 |
| 18 | 68590336573 |
| 19 | 274490486455 |
| 20 | 1098349366309 |
| 21 | 4394559726703 |
| 22 | 17581725691213 |
| 23 | 70337363118055 |