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 | 3 |
| 3 | 5 |
| 4 | 9 |
| 5 | 18 |
| 6 | 39 |
| 7 | 90 |
| 8 | 217 |
| 9 | 540 |
| 10 | 1375 |
| 11 | 3563 |
| 12 | 9361 |
| 13 | 24872 |
| 14 | 66707 |
| 15 | 180341 |
| 16 | 490913 |
| 17 | 1344380 |
| 18 | 3701159 |
| 19 | 10237541 |
| 20 | 28436825 |
| 21 | 79288844 |
| 22 | 221836403 |
| 23 | 622599626 |
| 24 | 1752360041 |
| 25 | 4945087838 |
| 26 | 13988490339 |
| 27 | 39658308815 |
| 28 | 112666081617 |