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 | 0 |
| 2 | 1 |
| 3 | -1 |
| 4 | 1 |
| 5 | -2 |
| 6 | 6 |
| 7 | -16 |
| 8 | 36 |
| 9 | -71 |
| 10 | 126 |
| 11 | -201 |
| 12 | 276 |
| 13 | -276 |
| 14 | 0 |
| 15 | 1014 |
| 16 | -3744 |
| 17 | 10179 |
| 18 | -24309 |
| 19 | 54126 |
| 20 | -115614 |
| 21 | 240444 |
| 22 | -490104 |
| 23 | 980209 |
| 24 | -1918752 |
| 25 | 3658449 |
| 26 | -6750224 |
| 27 | 11950524 |
| 28 | -20058300 |
| 29 | 31303782 |
| 30 | -43733304 |
| 31 | 49586229 |
| 32 | -28048799 |
| 33 | -67798986 |
| 34 | 331797126 |
| 35 | -932095976 |