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 | 45 |
| 7 | 315 |
| 8 | 2520 |
| 9 | 280 |
| 10 | 175 |
| 11 | 1925 |
| 12 | 23100 |
| 13 | 300300 |
| 14 | 4204200 |
| 15 | 63063000 |
| 16 | 63063000 |
| 17 | 1072071000 |
| 18 | 14889875 |
| 19 | 282907625 |
| 20 | 9053044 |
| 21 | 190113924 |
| 22 | 4182506328 |
| 23 | 96197645544 |
| 24 | 144296468316 |
| 25 | 3607411707900 |
| 26 | 93792704405400 |
| 27 | 31264234801800 |
| 28 | 22787343150 |
| 29 | 660832951350 |