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 | 0 |
| 1 | 1 |
| 2 | 5 |
| 3 | 32 |
| 4 | 236 |
| 5 | 1896 |
| 6 | 16116 |
| 7 | 142544 |
| 8 | 1298524 |
| 9 | 12100952 |
| 10 | 114820964 |
| 11 | 1105574400 |
| 12 | 10775285836 |
| 13 | 106098789832 |
| 14 | 1053858546516 |
| 15 | 10546951101360 |
| 16 | 106249238782652 |
| 17 | 1076554249491640 |
| 18 | 10964085715303620 |
| 19 | 112175072002688480 |