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 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 1 |
| 5 | 1 |
| 6 | 1 |
| 7 | 1 |
| 8 | 1 |
| 9 | 2 |
| 10 | 20 |
| 11 | 200 |
| 12 | 1520 |
| 13 | 9440 |
| 14 | 50624 |
| 15 | 242816 |
| 16 | 1066496 |
| 17 | 4361216 |
| 18 | 16856556 |
| 19 | 64202712 |
| 20 | 288983580 |
| 21 | 2160645840 |
| 22 | 24525417780 |
| 23 | 294825080160 |
| 24 | 3270522114228 |
| 25 | 32898687457422 |
| 26 | 302696887652022 |
| 27 | 2577419367939422 |
| 28 | 20537905525582022 |
| 29 | 155236628840778062 |