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) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 12 |
| 3 | 1 |
| 4 | 720 |
| 5 | 1 |
| 6 | 30240 |
| 7 | 1 |
| 8 | 1209600 |
| 9 | 1 |
| 10 | 47900160 |
| 11 | 1 |
| 12 | 1307674368000 |
| 13 | 1 |
| 14 | 74724249600 |
| 15 | 1 |
| 16 | 10670622842880000 |
| 17 | 1 |
| 18 | 5109094217170944000 |
| 19 | 1 |
| 20 | 802857662698291200000 |
| 21 | 1 |
| 22 | 14101100039391805440000 |
| 23 | 1 |
| 24 | 1693824136731743669452800000 |
| 25 | 1 |
| 26 | 186134520519971831808000000 |
| 27 | 1 |
| 28 | 37893265687455865519472640000000 |
| 29 | 1 |
| 30 | 759790291646040068357842010112000000 |
| 31 | 1 |