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 | -4 |
| 5 | 4 |
| 6 | -2 |
| 7 | 2 |
| 8 | 2 |
| 9 | -26 |
| 10 | 80 |
| 11 | -168 |
| 12 | 351 |
| 13 | -749 |
| 14 | 1485 |
| 15 | -2779 |
| 16 | 5134 |
| 17 | -9314 |
| 18 | 16318 |
| 19 | -27522 |
| 20 | 44596 |
| 21 | -68484 |
| 22 | 96148 |
| 23 | -113172 |
| 24 | 77125 |
| 25 | 122309 |
| 26 | -750801 |
| 27 | 2411307 |
| 28 | -6424162 |
| 29 | 15607886 |
| 30 | -35846784 |
| 31 | 79201548 |
| 32 | -170009469 |
| 33 | 356687423 |
| 34 | -734287141 |
| 35 | 1487086199 |
| 36 | -2967980133 |