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 | 2 |
| 3 | 8 |
| 4 | 26 |
| 5 | 82 |
| 6 | 262 |
| 7 | 856 |
| 8 | 2858 |
| 9 | 9722 |
| 10 | 33590 |
| 11 | 117570 |
| 12 | 416022 |
| 13 | 1485798 |
| 14 | 5348878 |
| 15 | 19389688 |
| 16 | 70715338 |
| 17 | 259289578 |
| 18 | 955277398 |
| 19 | 3534526378 |
| 20 | 13128240838 |
| 21 | 48932534038 |
| 22 | 182965127278 |
| 23 | 686119227298 |
| 24 | 2579808294646 |
| 25 | 9723892802902 |
| 26 | 36734706144302 |
| 27 | 139067101832006 |
| 28 | 527495903500718 |