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 | 0 |
| 5 | 2 |
| 6 | -1 |
| 7 | 5 |
| 8 | -7 |
| 9 | 15 |
| 10 | -35 |
| 11 | 57 |
| 12 | -155 |
| 13 | 262 |
| 14 | -664 |
| 15 | 1297 |
| 16 | -2910 |
| 17 | 6437 |
| 18 | -13428 |
| 19 | 31461 |
| 20 | -65137 |
| 21 | 152576 |
| 22 | -325838 |
| 23 | 744223 |
| 24 | -1649943 |
| 25 | 3685869 |
| 26 | -8376976 |
| 27 | 18574146 |
| 28 | -42579093 |
| 29 | 94912298 |
| 30 | -217177891 |
| 31 | 489321856 |
| 32 | -1114542791 |
| 33 | 2535640016 |
| 34 | -5761630456 |
| 35 | 13184657747 |
| 36 | -29989008137 |