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 | 347815 |
| 10 | 3448442 |
| 11 | 37608834 |
| 12 | 447450930 |
| 13 | 5767170785 |
| 14 | 80050654711 |
| 15 | 1190502148797 |
| 16 | 18885313699983 |
| 17 | 318307710883720 |
| 18 | 5680593325882836 |
| 19 | 107009253612595865 |
| 20 | 2121902210596869336 |
| 21 | 44179286193550935095 |
| 22 | 963641311893918317652 |