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 | 44 |
| 2 | 560 |
| 3 | 1786 |
| 4 | 0 |
| 5 | 95342 |
| 6 | 1264272 |
| 7 | 4213042 |
| 8 | 0 |
| 9 | 241384794 |
| 10 | 3259289000 |
| 11 | 11028760078 |
| 12 | 0 |
| 13 | 651843679214 |
| 14 | 8881641917904 |
| 15 | 30295985735960 |
| 16 | 0 |
| 17 | 1822122857478000 |
| 18 | 24962501190898560 |
| 19 | 85571276146432860 |
| 20 | 0 |
| 21 | 5204404120691796724 |