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 | 0 |
| 3 | 1 |
| 4 | 5 |
| 5 | 21 |
| 6 | 52 |
| 7 | 93 |
| 8 | 157 |
| 9 | 1615 |
| 10 | 3976 |
| 11 | 6063 |
| 12 | 38657 |
| 13 | 41029695 |
| 14 | 40060126 |
| 15 | 66408709 |
| 16 | 69552217 |
| 17 | 21794638335 |
| 18 | 1307902407752 |
| 19 | 355687428358143 |
| 20 | 355691118382363 |
| 21 | 10559506801336735 |
| 22 | 1267150213999726 |
| 23 | 2534272929378303 |
| 24 | 2548357888109546 |
| 25 | 1831184524199042148591 |