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 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 1 |
| 6 | 0 |
| 7 | 4 |
| 8 | 11 |
| 9 | 42 |
| 10 | 89 |
| 11 | 329 |
| 12 | 1765 |
| 13 | 9197 |
| 14 | 45647 |
| 15 | 284743 |
| 16 | 1846189 |
| 17 | 11975869 |
| 18 | 83259065 |
| 19 | 621001708 |
| 20 | 4878630533 |
| 21 | 39333230881 |
| 22 | 336375931369 |
| 23 | 3029241762900 |
| 24 | 28439270037332 |
| 25 | 275986675209470 |
| 26 | 2789712437580722 |