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 | 3 |
| 2 | 12 |
| 3 | 51 |
| 4 | 234 |
| 5 | 1110 |
| 6 | 5460 |
| 7 | 27405 |
| 8 | 140490 |
| 9 | 729918 |
| 10 | 3845016 |
| 11 | 20447658 |
| 12 | 109801692 |
| 13 | 593806356 |
| 14 | 3234529584 |
| 15 | 17715445605 |
| 16 | 97567971930 |
| 17 | 539701180590 |
| 18 | 2998595422680 |
| 19 | 16719506691030 |
| 20 | 93559970043540 |
| 21 | 525093580540620 |
| 22 | 2955822168597480 |
| 23 | 16680150247605390 |
| 24 | 94365481922990460 |