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 | 1 |
| 4 | 1 |
| 5 | 1 |
| 6 | 201 |
| 7 | 1226 |
| 8 | 5587 |
| 9 | 493333 |
| 10 | 8910253 |
| 11 | 109739620 |
| 12 | 6832444928 |
| 13 | 251336859489 |
| 14 | 6402632091649 |
| 15 | 369288128260091 |
| 16 | 21333939590516867 |
| 17 | 941843896620169405 |
| 18 | 60266201588496408645 |
| 19 | 4623833509894543300868 |
| 20 | 309412778502377193367456 |
| 21 | 24102475277979402591991181 |