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 | -2 |
| 2 | 1 |
| 3 | 3 |
| 4 | -8 |
| 5 | 7 |
| 6 | 7 |
| 7 | -30 |
| 8 | 37 |
| 9 | 7 |
| 10 | -104 |
| 11 | 171 |
| 12 | -53 |
| 13 | -326 |
| 14 | 721 |
| 15 | -501 |
| 16 | -872 |
| 17 | 2815 |
| 18 | -2945 |
| 19 | -1614 |
| 20 | 10189 |
| 21 | -14465 |
| 22 | 1048 |
| 23 | 33795 |
| 24 | -63773 |
| 25 | 32074 |
| 26 | 99289 |
| 27 | -258909 |
| 28 | 223768 |
| 29 | 233719 |
| 30 | -975305 |
| 31 | 1189122 |
| 32 | 253621 |
| 33 | -3393353 |
| 34 | 5517976 |
| 35 | -1617381 |
| 36 | -10687301 |
| 37 | 23340634 |
| 38 | -15888095 |
| 39 | -28827141 |
| 40 | 91396504 |