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 | 1 |
| 2 | 2 |
| 3 | 4 |
| 4 | 10 |
| 5 | 25 |
| 6 | 66 |
| 7 | 173 |
| 8 | 460 |
| 9 | 1218 |
| 10 | 3240 |
| 11 | 8602 |
| 12 | 22878 |
| 13 | 60794 |
| 14 | 161668 |
| 15 | 429752 |
| 16 | 1142758 |
| 17 | 3038173 |
| 18 | 8078606 |
| 19 | 21479469 |
| 20 | 57113888 |