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 | 347862 |
| 10 | 3449292 |
| 11 | 37622348 |
| 12 | 447662376 |
| 13 | 5770553184 |
| 14 | 80106726784 |
| 15 | 1191471740436 |
| 16 | 18902847341664 |
| 17 | 318639524995160 |
| 18 | 5687162644422552 |
| 19 | 107145206713313556 |
| 20 | 2124840033683212648 |
| 21 | 44245492380155416392 |
| 22 | 965195327390976439656 |