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) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 2 |
| 6 | 11 |
| 7 | 71 |
| 8 | 370 |
| 9 | 2005 |
| 10 | 10682 |
| 11 | 58167 |
| 12 | 320116 |
| 13 | 1789210 |
| 14 | 10121965 |
| 15 | 57933469 |
| 16 | 334919626 |
| 17 | 1953800059 |
| 18 | 11489466014 |
| 19 | 68053583772 |
| 20 | 405713887061 |
| 21 | 2433000197471 |
| 22 | 14668527134167 |
| 23 | 88869448492895 |
| 24 | 540834097467624 |
| 25 | 3304961431043989 |
| 26 | 20273201718862728 |
| 27 | 124798671079300720 |
| 28 | 770762029389852807 |