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 | 1 |
| 6 | 2 |
| 7 | 9 |
| 8 | 49 |
| 9 | 455 |
| 10 | 5784 |
| 11 | 90940 |
| 12 | 1620491 |
| 13 | 31478651 |
| 14 | 656784488 |
| 15 | 14621878339 |
| 16 | 345975756388 |