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 | 24 |
| 5 | 118 |
| 6 | 674 |
| 7 | 4306 |
| 8 | 29990 |
| 9 | 223668 |
| 10 | 1763468 |
| 11 | 14558588 |
| 12 | 124938648 |
| 13 | 1108243002 |
| 14 | 10115202962 |
| 15 | 94652608690 |
| 16 | 905339525594 |
| 17 | 8829466579404 |
| 18 | 87618933380020 |
| 19 | 883153699606024 |
| 20 | 9028070631668540 |
| 21 | 93478132393544988 |
| 22 | 979246950529815364 |
| 23 | 10368459385853924212 |