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) |
|---|---|
| 4 | 1 |
| 5 | 4 |
| 6 | 24 |
| 7 | 131 |
| 8 | 663 |
| 9 | 3252 |
| 10 | 15772 |
| 11 | 75415 |
| 12 | 359307 |
| 13 | 1711908 |
| 14 | 8191607 |
| 15 | 39500169 |
| 16 | 192525021 |
| 17 | 950868860 |
| 18 | 4769060224 |
| 19 | 24331970791 |
| 20 | 126457607026 |
| 21 | 670143402073 |
| 22 | 3623530476832 |
| 23 | 19998343352758 |
| 24 | 112668088476243 |
| 25 | 647904733883526 |