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 | 6 |
| 3 | 48 |
| 4 | 282 |
| 5 | 1476 |
| 6 | 7302 |
| 7 | 35016 |
| 8 | 164850 |
| 9 | 767340 |
| 10 | 3546366 |
| 11 | 16315248 |
| 12 | 74837802 |
| 13 | 342621396 |
| 14 | 1566620022 |
| 15 | 7157423256 |
| 16 | 32682574050 |
| 17 | 149184117180 |
| 18 | 680813718126 |
| 19 | 3106475197248 |
| 20 | 14173073072922 |
| 21 | 64659388538916 |
| 22 | 294971717255142 |
| 23 | 1345602571317096 |
| 24 | 6138257708432850 |