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 | 1 |
| 4 | 24 |
| 5 | 2040 |
| 6 | 297200 |
| 7 | 68938800 |
| 8 | 24046189440 |
| 9 | 12025780892160 |
| 10 | 8302816499443200 |
| 11 | 7673688777463632000 |
| 12 | 9254768770160124288000 |
| 13 | 14255616537578735986867200 |
| 14 | 27537152449960680597739468800 |
| 15 | 65662040698002721810659005184000 |