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 | 0 |
| 2 | 0 |
| 3 | 6 |
| 4 | 9 |
| 5 | 36 |
| 6 | 99 |
| 7 | 342 |
| 8 | 1188 |
| 9 | 4314 |
| 10 | 16308 |
| 11 | 61362 |
| 12 | 244344 |
| 13 | 969480 |
| 14 | 3990681 |
| 15 | 16401402 |
| 16 | 69105645 |
| 17 | 292097790 |
| 18 | 1254450831 |
| 19 | 5412716802 |
| 20 | 23608046241 |
| 21 | 103512674946 |
| 22 | 457382482686 |
| 23 | 2031136391286 |
| 24 | 9072992530731 |