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 | 3 |
| 4 | 4 |
| 5 | -15 |
| 6 | -134 |
| 7 | -357 |
| 8 | 2374 |
| 9 | 33645 |
| 10 | 133186 |
| 11 | -1288617 |
| 12 | -24887906 |
| 13 | -130115895 |
| 14 | 1666879306 |
| 15 | 40612637523 |
| 16 | 262868197414 |
| 17 | -4221449488635 |
| 18 | -123802488449774 |
| 19 | -952293015617937 |
| 20 | 18497401668708334 |
| 21 | 632675912865355425 |
| 22 | 5622243546094977946 |
| 23 | -128799294291220310997 |