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 | 1 |
| 2 | 0 |
| 3 | 0 |
| 4 | 2 |
| 5 | 8 |
| 6 | 98 |
| 7 | 1844 |
| 8 | 38039 |
| 9 | 949738 |
| 10 | 24643236 |
| 11 | 947689757 |
| 12 | 45828982764 |
| 13 | 2151748695931 |
| 14 | 123821075526032 |
| 15 | 8131094055190149 |
| 16 | 573957471153552576 |
| 17 | 44010987379157415768 |
| 18 | 3655486139293429450720 |
| 19 | 333633403912637510806972 |