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) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 24 |
| 5 | 120 |
| 6 | 701 |
| 7 | 4774 |
| 8 | 37128 |
| 9 | 326089 |
| 10 | 3184221 |
| 11 | 34191983 |
| 12 | 400308461 |
| 13 | 5076257396 |
| 14 | 69329710171 |
| 15 | 1014612340743 |
| 16 | 15838898430094 |
| 17 | 262706269352374 |
| 18 | 4613506518038420 |
| 19 | 85520547931176984 |
| 20 | 1668736482655334275 |
| 21 | 34189755475407632542 |
| 22 | 733851215342599413848 |