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 | -5 |
| 2 | 5 |
| 3 | 35 |
| 4 | 165 |
| 5 | 1075 |
| 6 | 10805 |
| 7 | 152035 |
| 8 | 2719365 |
| 9 | 58547475 |
| 10 | 1469512405 |
| 11 | 42082036035 |
| 12 | 1353220758565 |
| 13 | 48264167285875 |
| 14 | 1890433757030005 |
| 15 | 80656857839376035 |
| 16 | 3723074712045197765 |
| 17 | 184851684577600696275 |
| 18 | 9822823990059902723605 |
| 19 | 556226222504163445932035 |