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 | 6 |
| 2 | 24 |
| 3 | 96 |
| 4 | 354 |
| 5 | 1326 |
| 6 | 4926 |
| 7 | 18210 |
| 8 | 67326 |
| 9 | 247722 |
| 10 | 910728 |
| 11 | 3341904 |
| 12 | 12249210 |
| 13 | 44852280 |
| 14 | 164073078 |
| 15 | 599739906 |
| 16 | 2190683418 |
| 17 | 7997186088 |
| 18 | 29178065364 |
| 19 | 106405678806 |
| 20 | 387867574110 |
| 21 | 1413283574238 |