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 | 0 |
| 4 | 0 |
| 5 | 0 |
| 6 | 1 |
| 7 | 21 |
| 8 | 266 |
| 9 | 2646 |
| 10 | 22827 |
| 11 | 179487 |
| 12 | 1324114 |
| 13 | 9357348 |
| 14 | 64991927 |
| 15 | 469882413 |
| 16 | 4008715074 |
| 17 | 46160063586 |
| 18 | 691114045987 |
| 19 | 11535301966755 |
| 20 | 194240576089826 |
| 21 | 3186376950695400 |
| 22 | 50592286213334943 |
| 23 | 780299037934036929 |
| 24 | 11788245937182037114 |