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 | 0 |
| 2 | 2 |
| 3 | 0 |
| 4 | 16 |
| 5 | 0 |
| 6 | 264 |
| 7 | 0 |
| 8 | 6828 |
| 9 | 0 |
| 10 | 218192 |
| 11 | 0 |
| 12 | 7555444 |
| 13 | 0 |
| 14 | 269039512 |
| 15 | 0 |
| 16 | 9671837852 |
| 17 | 0 |
| 18 | 348829877760 |
| 19 | 0 |
| 20 | 12595130308612 |
| 21 | 0 |
| 22 | 454944702478600 |
| 23 | 0 |
| 24 | 16435098767896556 |
| 25 | 0 |
| 26 | 593753325451468144 |
| 27 | 0 |
| 28 | 21450960845508768532 |
| 29 | 0 |
| 30 | 774978877336933136632 |
| 31 | 0 |