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 | 6 |
| 3 | 51 |
| 4 | 561 |
| 5 | 7556 |
| 6 | 120196 |
| 7 | 2201856 |
| 8 | 45592666 |
| 9 | 1051951026 |
| 10 | 26740775306 |
| 11 | 742069051906 |
| 12 | 22310563733864 |
| 13 | 722108667742546 |
| 14 | 25024187820786357 |
| 15 | 924161461265888370 |
| 16 | 36223781285638309482 |
| 17 | 1501552062016443881514 |