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 | 6 |
| 4 | 24 |
| 5 | 120 |
| 6 | 720 |
| 7 | 5040 |
| 8 | 40320 |
| 9 | 362880 |
| 10 | 14175 |
| 11 | 155925 |
| 12 | 1871100 |
| 13 | 24324300 |
| 14 | 340540200 |
| 15 | 5108103000 |
| 16 | 81729648000 |
| 17 | 1389404016000 |
| 18 | 14889875 |
| 19 | 282907625 |
| 20 | 5658152500 |
| 21 | 118821202500 |
| 22 | 2614066455000 |
| 23 | 60123528465000 |
| 24 | 1442964683160000 |
| 25 | 36074117079000000 |