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 | 2 |
| 2 | 6 |
| 3 | 20 |
| 4 | 96 |
| 5 | 646 |
| 6 | 7664 |
| 7 | 172924 |
| 8 | 8114872 |
| 9 | 781726816 |
| 10 | 158475666938 |
| 11 | 65399255831376 |