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) |
|---|---|
| 2 | 1 |
| 3 | 6 |
| 4 | 26 |
| 5 | 120 |
| 6 | 594 |
| 7 | 3094 |
| 8 | 16728 |
| 9 | 93024 |
| 10 | 528770 |
| 11 | 3058770 |
| 12 | 17948970 |
| 13 | 106585440 |
| 14 | 639318456 |
| 15 | 3867821640 |
| 16 | 23574446992 |
| 17 | 144621823632 |
| 18 | 892293152994 |
| 19 | 5533289372170 |
| 20 | 34468829508750 |
| 21 | 215594574231960 |
| 22 | 1353464311979010 |