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 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 24 |
| 5 | 119 |
| 6 | 708 |
| 7 | 4914 |
| 8 | 38980 |
| 9 | 347837 |
| 10 | 3448792 |
| 11 | 37614098 |
| 12 | 447531000 |
| 13 | 5768428803 |
| 14 | 80071254648 |
| 15 | 1190855183414 |
| 16 | 18891654561628 |
| 17 | 318427067939961 |
| 18 | 5682946188447440 |
| 19 | 107057773100175102 |
| 20 | 2122947536807150960 |
| 21 | 44202783404925357767 |
| 22 | 964191633859884115696 |