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 | 1 |
| 2 | 1 |
| 3 | 2 |
| 4 | 4 |
| 5 | 12 |
| 6 | 34 |
| 7 | 125 |
| 8 | 450 |
| 9 | 1780 |
| 10 | 7021 |
| 11 | 28521 |
| 12 | 115553 |
| 13 | 472578 |
| 14 | 1927634 |
| 15 | 7890893 |
| 16 | 32221475 |
| 17 | 131812746 |
| 18 | 538059836 |
| 19 | 2198986587 |
| 20 | 8970624060 |
| 21 | 36628143111 |
| 22 | 149328243327 |
| 23 | 609238673619 |