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 | -3 |
| 2 | 0 |
| 3 | -1 |
| 4 | 18 |
| 5 | -12 |
| 6 | 11 |
| 7 | -54 |
| 8 | 84 |
| 9 | -218 |
| 10 | 243 |
| 11 | -270 |
| 12 | 1046 |
| 13 | -1524 |
| 14 | 1692 |
| 15 | -3547 |
| 16 | 7722 |
| 17 | -11868 |
| 18 | 15364 |
| 19 | -29130 |
| 20 | 52416 |
| 21 | -83467 |
| 22 | 125514 |
| 23 | -190716 |
| 24 | 380406 |
| 25 | -628290 |
| 26 | 808218 |
| 27 | -1394734 |
| 28 | 2585895 |
| 29 | -3784566 |
| 30 | 5678826 |
| 31 | -9514614 |
| 32 | 15635424 |
| 33 | -25331990 |
| 34 | 37563810 |
| 35 | -57387042 |
| 36 | 100038145 |
| 37 | -156346224 |