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) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 3 |
| 4 | 16 |
| 5 | 130 |
| 6 | 1485 |
| 7 | 22645 |
| 8 | 444136 |
| 9 | 10889676 |
| 10 | 326345460 |
| 11 | 11736144420 |
| 12 | 498798542880 |
| 13 | 24732729791484 |
| 14 | 1415034219327729 |
| 15 | 92523874454996985 |
| 16 | 6856434802243346320 |
| 17 | 571604206230905727880 |
| 18 | 53259509403796625217288 |
| 19 | 5513868420471764306104008 |