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 | 0 |
| 1 | 0 |
| 2 | 1 |
| 3 | 9 |
| 4 | 36 |
| 5 | 101 |
| 6 | 261 |
| 7 | 882 |
| 8 | 3921 |
| 9 | 17253 |
| 10 | 67554 |
| 11 | 243695 |
| 12 | 876789 |
| 13 | 3324906 |
| 14 | 13166791 |
| 15 | 52301709 |
| 16 | 203824548 |
| 17 | 782913717 |
| 18 | 3010327497 |
| 19 | 11695756698 |
| 20 | 45823049817 |
| 21 | 179787741723 |
| 22 | 703527078258 |
| 23 | 2747647985241 |
| 24 | 10739885115573 |
| 25 | 42082084255050 |
| 26 | 165225573240651 |