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 | -3 |
| 2 | 0 |
| 3 | 9 |
| 4 | -12 |
| 5 | 0 |
| 6 | 27 |
| 7 | -42 |
| 8 | 0 |
| 9 | 82 |
| 10 | -111 |
| 11 | 0 |
| 12 | 207 |
| 13 | -279 |
| 14 | 0 |
| 15 | 486 |
| 16 | -630 |
| 17 | 0 |
| 18 | 1055 |
| 19 | -1362 |
| 20 | 0 |
| 21 | 2205 |
| 22 | -2775 |
| 23 | 0 |
| 24 | 4374 |
| 25 | -5472 |
| 26 | 0 |
| 27 | 8427 |
| 28 | -10389 |
| 29 | 0 |
| 30 | 15696 |
| 31 | -19224 |
| 32 | 0 |
| 33 | 28539 |
| 34 | -34614 |
| 35 | 0 |
| 36 | 50630 |
| 37 | -61059 |
| 38 | 0 |
| 39 | 88119 |
| 40 | -105483 |
| 41 | 0 |
| 42 | 150417 |
| 43 | -179178 |
| 44 | 0 |
| 45 | 252727 |
| 46 | -299325 |
| 47 | 0 |
| 48 | 418068 |