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 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 1 |
| 5 | -2 |
| 6 | 3 |
| 7 | -4 |
| 8 | 6 |
| 9 | -10 |
| 10 | 17 |
| 11 | -28 |
| 12 | 45 |
| 13 | -72 |
| 14 | 116 |
| 15 | -188 |
| 16 | 305 |
| 17 | -494 |
| 18 | 799 |
| 19 | -1292 |
| 20 | 2090 |
| 21 | -3382 |
| 22 | 5473 |
| 23 | -8856 |
| 24 | 14329 |
| 25 | -23184 |
| 26 | 37512 |
| 27 | -60696 |
| 28 | 98209 |
| 29 | -158906 |
| 30 | 257115 |
| 31 | -416020 |
| 32 | 673134 |
| 33 | -1089154 |
| 34 | 1762289 |
| 35 | -2851444 |
| 36 | 4613733 |
| 37 | -7465176 |
| 38 | 12078908 |
| 39 | -19544084 |
| 40 | 31622993 |