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 | 43 |
| 4 | 108 |
| 5 | 444 |
| 6 | 2099 |
| 7 | 10683 |
| 8 | 56994 |
| 9 | 314296 |
| 10 | 1776519 |
| 11 | 10236081 |
| 12 | 59892690 |
| 13 | 354886920 |
| 14 | 2125117332 |
| 15 | 12839859620 |
| 16 | 78176677734 |
| 17 | 479177993904 |
| 18 | 2954360065247 |
| 19 | 18309779343549 |
| 20 | 114001476318240 |
| 21 | 712751759478780 |
| 22 | 4472908385838795 |
| 23 | 28165267333869435 |