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 | 43 |
| 4 | 2150 |
| 5 | 105050 |
| 6 | 5149551 |
| 7 | 252313293 |
| 8 | 12363454300 |
| 9 | 605808540100 |
| 10 | 29684623509101 |
| 11 | 1454546516636543 |
| 12 | 71272779562356450 |
| 13 | 3492366196825305150 |
| 14 | 171125943656551078651 |
| 15 | 8385171239086224969793 |
| 16 | 410873390715818468708600 |
| 17 | 20132796145070950850400200 |