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 | 1 |
| 3 | 3 |
| 4 | 0 |
| 5 | 30 |
| 6 | 246 |
| 7 | 0 |
| 8 | 25321 |
| 9 | 591103 |
| 10 | 0 |
| 11 | 603105309 |
| 12 | 41333676318 |
| 13 | 0 |
| 14 | 410382321560202 |
| 15 | 83918368144461643 |
| 16 | 0 |
| 17 | 8025244898075570226296 |
| 18 | 4941312847984149589980261 |