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) |
|---|---|
| 7 | 1 |
| 8 | -1640 |
| 9 | 4035220 |
| 10 | -8509702520 |
| 11 | 18843459775162 |
| 12 | -41041673208656120 |
| 13 | 89881489830655851460 |
| 14 | -196480936769813691291560 |
| 15 | 429769342296322230713871283 |
| 16 | -939857780045414554730512966640 |