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 | 38979 |
| 9 | 347844 |
| 10 | 3449022 |
| 11 | 37618404 |
| 12 | 447603154 |
| 13 | 5769631250 |
| 14 | 80091726847 |
| 15 | 1191215895231 |
| 16 | 18898269051750 |
| 17 | 318553597247225 |
| 18 | 5685472764793353 |
| 19 | 107110426612465623 |
| 20 | 2124091932221770696 |
| 21 | 44228699419853376368 |
| 22 | 964802486928888810542 |