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 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 24 |
| 5 | 120 |
| 6 | 720 |
| 7 | 5040 |
| 8 | 40320 |
| 9 | 100736 |
| 10 | 483072 |
| 11 | 2168064 |
| 12 | 9239552 |
| 13 | 53005312 |
| 14 | 205203456 |
| 15 | 930568192 |
| 16 | 2004189184 |
| 17 | 12596379648 |
| 18 | 54936141824 |
| 19 | 81714020352 |
| 20 | 534768779264 |
| 21 | 1334539714560 |
| 22 | 2971594653696 |
| 23 | 68346677035008 |
| 24 | 232945365286912 |
| 25 | 1038559528091648 |
| 26 | 2232749779845120 |