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 | 3 |
| 1 | 16 |
| 2 | 85 |
| 3 | 451 |
| 4 | 2392 |
| 5 | 12686 |
| 6 | 67280 |
| 7 | 356818 |
| 8 | 1892376 |
| 9 | 10036172 |
| 10 | 53226604 |
| 11 | 282286052 |
| 12 | 1497097488 |
| 13 | 7939821584 |
| 14 | 42108658448 |
| 15 | 223322287224 |
| 16 | 1184384537744 |
| 17 | 6281355751296 |
| 18 | 33313023614352 |
| 19 | 176674843181968 |
| 20 | 936990907061504 |
| 21 | 4969309405367264 |
| 22 | 26354616443092800 |
| 23 | 139771093164846816 |
| 24 | 741272730213321216 |
| 25 | 3931322622695991104 |