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 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 1 |
| 6 | 3 |
| 7 | 9 |
| 8 | 28 |
| 9 | 85 |
| 10 | 262 |
| 11 | 827 |
| 12 | 2651 |
| 13 | 8626 |
| 14 | 28507 |
| 15 | 95393 |
| 16 | 322938 |
| 17 | 1104525 |
| 18 | 3812367 |
| 19 | 13266366 |
| 20 | 46504495 |
| 21 | 164098390 |
| 22 | 582521687 |
| 23 | 2079133141 |
| 24 | 7457788295 |
| 25 | 26872946466 |
| 26 | 97238824018 |
| 27 | 353218128299 |
| 28 | 1287657977946 |
| 29 | 4709784136316 |