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 | 0 |
| 1 | 0 |
| 2 | 1 |
| 3 | 3 |
| 4 | 0 |
| 5 | 10 |
| 6 | 75 |
| 7 | 126 |
| 8 | 196 |
| 9 | 1548 |
| 10 | 15525 |
| 11 | 39820 |
| 12 | 161106 |
| 13 | 358722 |
| 14 | 3705884 |
| 15 | 46623045 |
| 16 | 142988280 |
| 17 | 768721504 |
| 18 | 3560215293 |
| 19 | 12250746432 |
| 20 | 144581799790 |
| 21 | 2542575063630 |
| 22 | 8955836934660 |
| 23 | 55657973021431 |
| 24 | 319349051391228 |
| 25 | 1983548989621200 |
| 26 | 7898257536096850 |