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 | 4 |
| 2 | 9 |
| 3 | 115 |
| 4 | 720 |
| 5 | 2476 |
| 6 | 42471 |
| 7 | 4765 |
| 8 | 1788961 |
| 9 | 3780956 |
| 10 | 51872200 |
| 11 | 310486445 |
| 12 | 1142532559 |
| 13 | 18483128564 |
| 14 | 4205436520 |
| 15 | 799862636324 |
| 16 | 1584162310079 |
| 17 | 23384002313285 |
| 18 | 133802323596440 |
| 19 | 526151093402156 |
| 20 | 8041209044472401 |
| 21 | 2783579583540395 |
| 22 | 357525366658772391 |