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 | 2 |
| 1 | 4 |
| 2 | 13 |
| 3 | -176 |
| 4 | -786 |
| 5 | -3452 |
| 6 | 54483 |
| 7 | 237722 |
| 8 | 1037569 |
| 9 | -16329149 |
| 10 | -71279530 |
| 11 | -311145495 |
| 12 | 4897036897 |
| 13 | 21376227709 |
| 14 | 93310132523 |
| 15 | -1468582101731 |
| 16 | -6410560285891 |
| 17 | -27982966049682 |
| 18 | 440416091468393 |
| 19 | 1922476035761802 |
| 20 | 8391868916275609 |