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 | 0 |
| 3 | -2 |
| 4 | 26 |
| 5 | 0 |
| 6 | 0 |
| 7 | 32560 |
| 8 | 130812 |
| 9 | 0 |
| 10 | 0 |
| 11 | 3671562 |
| 12 | 9174424 |
| 13 | 0 |
| 14 | 0 |
| 15 | 95675472 |
| 16 | 188233758 |
| 17 | 0 |
| 18 | 0 |
| 19 | 1142977594 |
| 20 | 1959731160 |
| 21 | 0 |
| 22 | 0 |
| 23 | 8506658544 |
| 24 | 13293118872 |
| 25 | 0 |
| 26 | 0 |
| 27 | 45762829976 |
| 28 | 67073331776 |
| 29 | 0 |
| 30 | 0 |
| 31 | 195388726752 |
| 32 | 272567835540 |
| 33 | 0 |
| 34 | 0 |
| 35 | 698077270836 |
| 36 | 938806082418 |
| 37 | 0 |
| 38 | 0 |
| 39 | 2176652437872 |