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 | 0 |
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 3388 |
| 5 | 157000 |
| 6 | 2135356 |
| 7 | 15836664 |
| 8 | 81324796 |
| 9 | 325679904 |
| 10 | 1088989348 |
| 11 | 3174085648 |
| 12 | 8301786980 |
| 13 | 19888285976 |
| 14 | 44304931948 |
| 15 | 92833927816 |
| 16 | 184597383660 |
| 17 | 350812701616 |
| 18 | 640815379476 |
| 19 | 1130391980512 |
| 20 | 1933082192404 |
| 21 | 3215240556392 |
| 22 | 5215796556572 |
| 23 | 8271817286296 |