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 | 0 |
| 2 | 1 |
| 3 | 1 |
| 4 | 6 |
| 5 | 1 |
| 6 | 120 |
| 7 | 1 |
| 8 | 840 |
| 9 | 10080 |
| 10 | 30240 |
| 11 | 1 |
| 12 | 3659040 |
| 13 | 1 |
| 14 | 17297280 |
| 15 | 3632428800 |
| 16 | 259459200 |
| 17 | 1 |
| 18 | 1490852563200 |
| 19 | 1 |
| 20 | 845092863014400 |
| 21 | 3379030566912000 |
| 22 | 28158588057600 |
| 23 | 1 |
| 24 | 2565331847811532800 |
| 25 | 1077167364120207360000 |
| 26 | 64764752532480000 |
| 27 | 5001134190558105600000 |