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 | 1 |
| 2 | 2 |
| 3 | 0 |
| 4 | 6 |
| 5 | 1 |
| 6 | 0 |
| 7 | 24 |
| 8 | 15 |
| 9 | 0 |
| 10 | 0 |
| 11 | 120 |
| 12 | 276 |
| 13 | 20 |
| 14 | 0 |
| 15 | 0 |
| 16 | 720 |
| 17 | 7140 |
| 18 | 2024 |
| 19 | 15 |
| 20 | 0 |
| 21 | 0 |
| 22 | 5040 |
| 23 | 258840 |
| 24 | 280840 |
| 25 | 10626 |
| 26 | 6 |
| 27 | 0 |
| 28 | 0 |
| 29 | 40320 |
| 30 | 12698280 |
| 31 | 61949040 |
| 32 | 8214570 |
| 33 | 42504 |
| 34 | 1 |
| 35 | 0 |
| 36 | 0 |
| 37 | 362880 |
| 38 | 812831040 |
| 39 | 21324644880 |
| 40 | 11104365420 |
| 41 | 190578024 |
| 42 | 134596 |
| 43 | 0 |
| 44 | 0 |
| 45 | 0 |
| 46 | 3628800 |