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) |
|---|---|
| 2 | 1 |
| 3 | 4 |
| 4 | 6 |
| 5 | 26 |
| 6 | 104 |
| 7 | 548 |
| 8 | 3366 |
| 9 | 24034 |
| 10 | 195168 |
| 11 | 1777652 |
| 12 | 17950550 |
| 13 | 199059674 |
| 14 | 2405063016 |
| 15 | 31448531956 |
| 16 | 442501797654 |
| 17 | 6666753146498 |
| 18 | 107081325959936 |
| 19 | 1826636018849444 |