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 | 0 |
| 3 | 1 |
| 4 | -2 |
| 5 | 2 |
| 6 | -1 |
| 7 | -1 |
| 8 | 4 |
| 9 | -9 |
| 10 | 16 |
| 11 | -19 |
| 12 | 1 |
| 13 | 59 |
| 14 | -158 |
| 15 | 229 |
| 16 | -129 |
| 17 | -297 |
| 18 | 1066 |
| 19 | -1878 |
| 20 | 1992 |
| 21 | -216 |
| 22 | -4862 |
| 23 | 13912 |
| 24 | -24258 |
| 25 | 25406 |
| 26 | 4162 |
| 27 | -90120 |
| 28 | 233708 |
| 29 | -359262 |
| 30 | 264319 |
| 31 | 360325 |
| 32 | -1745699 |
| 33 | 3624263 |
| 34 | -4623550 |
| 35 | 1795485 |
| 36 | 8918014 |
| 37 | -29893776 |
| 38 | 55251854 |
| 39 | -61018833 |
| 40 | -1455525 |