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 | 20 |
| 5 | 72 |
| 6 | 274 |
| 7 | 1088 |
| 8 | 4470 |
| 9 | 18884 |
| 10 | 81652 |
| 11 | 360054 |
| 12 | 1614618 |
| 13 | 7346688 |
| 14 | 33856008 |
| 15 | 157777908 |
| 16 | 742637416 |