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 | 3 |
| 2 | 24 |
| 3 | 282 |
| 4 | 4416 |
| 5 | 86448 |
| 6 | 2030784 |
| 7 | 55656912 |
| 8 | 1743277056 |
| 9 | 61427981568 |
| 10 | 2405046994944 |
| 11 | 103579443604992 |
| 12 | 4866448609591296 |
| 13 | 247692476576575488 |
| 14 | 13576823521525653504 |
| 15 | 797345878311609526272 |
| 16 | 49948684871884896731136 |
| 17 | 3324530341927517641310208 |
| 18 | 234293439367907438337982464 |