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 | 0 |
| 6 | 0 |
| 7 | 0 |
| 8 | 0 |
| 9 | 0 |
| 10 | 1 |
| 11 | 32 |
| 12 | 1088 |
| 13 | 17280 |
| 14 | 293832 |
| 15 | 4004352 |
| 16 | 57687080 |
| 17 | 773838336 |
| 18 | 10900027949 |
| 19 | 151388845568 |
| 20 | 2200665880514 |
| 21 | 32321771402240 |
| 22 | 495575856116168 |
| 23 | 7760560549644288 |
| 24 | 126552637539515688 |