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 | 0 |
| 3 | 0 |
| 4 | 11 |
| 5 | 96 |
| 6 | 798 |
| 7 | 6197 |
| 8 | 54400 |
| 9 | 505503 |
| 10 | 5241223 |
| 11 | 58377002 |
| 12 | 712436696 |
| 13 | 9315437345 |
| 14 | 131487856629 |
| 15 | 1978064399766 |
| 16 | 31777977184459 |
| 17 | 541010185315536 |
| 18 | 9758067888585784 |
| 19 | 185538235462354828 |
| 20 | 3714549428287398782 |