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 | 2 |
| 3 | 6 |
| 4 | 24 |
| 5 | 120 |
| 6 | 720 |
| 7 | 5040 |
| 8 | 40320 |
| 9 | 5040 |
| 10 | 45360 |
| 11 | 95760 |
| 12 | 332640 |
| 13 | 1426320 |
| 14 | 7464240 |
| 15 | 46211760 |
| 16 | 330946560 |
| 17 | 2693784240 |
| 18 | 661893120 |
| 19 | 6049461600 |
| 20 | 13422709440 |
| 21 | 52367051520 |
| 22 | 236313624960 |
| 23 | 1286302227840 |
| 24 | 8190440616960 |
| 25 | 59905688774400 |