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) |
|---|---|
| 1 | 1 |
| 2 | 0 |
| 3 | 1 |
| 4 | -3 |
| 5 | 6 |
| 6 | -9 |
| 7 | 9 |
| 8 | 0 |
| 9 | -27 |
| 10 | 81 |
| 11 | -161 |
| 12 | 231 |
| 13 | -165 |
| 14 | -363 |
| 15 | 2079 |
| 16 | -6435 |
| 17 | 16071 |
| 18 | -35343 |
| 19 | 70686 |
| 20 | -130339 |
| 21 | 222717 |
| 22 | -352715 |
| 23 | 515944 |
| 24 | -692967 |
| 25 | 849299 |
| 26 | -950455 |
| 27 | 996435 |
| 28 | -1042415 |
| 29 | 1042415 |
| 30 | 0 |
| 31 | -6926040 |
| 32 | 36515985 |
| 33 | -137544209 |
| 34 | 436316441 |
| 35 | -1233171500 |
| 36 | 3195484765 |