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 | 2 |
| 2 | 4 |
| 3 | 8 |
| 4 | 17 |
| 5 | 38 |
| 6 | 89 |
| 7 | 216 |
| 8 | 539 |
| 9 | 1374 |
| 10 | 3562 |
| 11 | 9360 |
| 12 | 24871 |
| 13 | 66706 |
| 14 | 180340 |
| 15 | 490912 |
| 16 | 1344379 |
| 17 | 3701158 |
| 18 | 10237540 |
| 19 | 28436824 |
| 20 | 79288843 |
| 21 | 221836402 |
| 22 | 622599625 |
| 23 | 1752360040 |
| 24 | 4945087837 |
| 25 | 13988490338 |
| 26 | 39658308814 |
| 27 | 112666081616 |