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 | 15 |
| 5 | -3 |
| 6 | 8 |
| 7 | -42 |
| 8 | 6 |
| 9 | -83 |
| 10 | 81 |
| 11 | -39 |
| 12 | 316 |
| 13 | -90 |
| 14 | 420 |
| 15 | -603 |
| 16 | 363 |
| 17 | -1656 |
| 18 | 625 |
| 19 | -2556 |
| 20 | 2877 |
| 21 | -2599 |
| 22 | 7818 |
| 23 | -3483 |
| 24 | 13886 |
| 25 | -11049 |
| 26 | 17040 |
| 27 | -31493 |
| 28 | 20196 |
| 29 | -63876 |
| 30 | 39244 |
| 31 | -96453 |
| 32 | 105891 |
| 33 | -120431 |
| 34 | 243333 |
| 35 | -164100 |
| 36 | 440873 |
| 37 | -327387 |
| 38 | 643968 |
| 39 | -765115 |
| 40 | 840207 |