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 | 1260 |
| 9 | 11340 |
| 10 | 113400 |
| 11 | 1247400 |
| 12 | 1925 |
| 13 | 25025 |
| 14 | 350350 |
| 15 | 5255250 |
| 16 | 2627625 |
| 17 | 44669625 |
| 18 | 804053250 |
| 19 | 15277011750 |
| 20 | 305540235000 |
| 21 | 6416344935000 |
| 22 | 141159588570000 |
| 23 | 3246670537110000 |
| 24 | 10020588077500 |
| 25 | 80164704620 |
| 26 | 2084282320120 |
| 27 | 56275622643240 |