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 | 2 |
| 2 | 2 |
| 3 | 8 |
| 4 | 3 |
| 5 | 384 |
| 6 | 40 |
| 7 | 23040 |
| 8 | 630 |
| 9 | 1146880 |
| 10 | 72576 |
| 11 | 1857945600 |
| 12 | 3326400 |
| 13 | 108999475200 |
| 14 | 148262400 |
| 15 | 2645053931520 |
| 16 | 13621608000 |
| 17 | 457065319366656000 |
| 18 | 75277762560 |
| 19 | 33566877054287216640 |
| 20 | 243290200817664 |