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) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 1 |
| 4 | 1 |
| 5 | 0 |
| 6 | 0 |
| 7 | 26 |
| 8 | 150 |
| 9 | 0 |
| 10 | 0 |
| 11 | 17792 |
| 12 | 108144 |
| 13 | 0 |
| 14 | 0 |
| 15 | 39809640 |
| 16 | 326721800 |
| 17 | 0 |
| 18 | 0 |
| 19 | 256814891280 |
| 20 | 2636337861200 |
| 21 | 0 |
| 22 | 0 |
| 23 | 3799455942515488 |
| 24 | 46845158056515936 |
| 25 | 0 |
| 26 | 0 |
| 27 | 111683611098764903232 |
| 28 | 1607383260609382393152 |
| 29 | 0 |
| 30 | 0 |