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) |
|---|---|
| 3 | 60 |
| 4 | 120 |
| 5 | 420 |
| 6 | 1200 |
| 7 | 3660 |
| 8 | 10920 |
| 9 | 32820 |
| 10 | 98400 |
| 11 | 295260 |
| 12 | 885720 |
| 13 | 2657220 |
| 14 | 7971600 |
| 15 | 23914860 |
| 16 | 71744520 |
| 17 | 215233620 |
| 18 | 645700800 |
| 19 | 1937102460 |
| 20 | 5811307320 |
| 21 | 17433922020 |
| 22 | 52301766000 |
| 23 | 156905298060 |
| 24 | 470715894120 |
| 25 | 1412147682420 |
| 26 | 4236443047200 |
| 27 | 12709329141660 |