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 | 1 |
| 2 | 1 |
| 3 | 3 |
| 4 | 1 |
| 5 | 5 |
| 6 | -26 |
| 7 | -75 |
| 8 | -430 |
| 9 | -1183 |
| 10 | -4249 |
| 11 | -10191 |
| 12 | -27443 |
| 13 | -42735 |
| 14 | -35715 |
| 15 | 341250 |
| 16 | 2073952 |
| 17 | 9886007 |
| 18 | 36365567 |
| 19 | 124484714 |
| 20 | 364966293 |
| 21 | 965150205 |
| 22 | 1958034669 |
| 23 | 2048555297 |
| 24 | -9110607428 |
| 25 | -76703557685 |
| 26 | -383500583452 |
| 27 | -1539890758482 |
| 28 | -5456784935108 |
| 29 | -17115737273816 |