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 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 21 |
| 5 | 86 |
| 6 | 404 |
| 7 | 2121 |
| 8 | 12264 |
| 9 | 77272 |
| 10 | 525941 |
| 11 | 3839706 |
| 12 | 29891370 |
| 13 | 246906569 |
| 14 | 2154904856 |
| 15 | 19799299506 |
| 16 | 190904273049 |
| 17 | 1926229186162 |
| 18 | 20288311652672 |
| 19 | 222568337565537 |
| 20 | 2537998989244956 |
| 21 | 30029233006187756 |
| 22 | 368050599579654557 |
| 23 | 4665833729558724030 |