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 | 2 |
| 3 | -2 |
| 4 | 0 |
| 5 | 0 |
| 6 | -2 |
| 7 | 2 |
| 8 | -4 |
| 9 | 0 |
| 10 | -2 |
| 11 | -6 |
| 12 | 0 |
| 13 | -10 |
| 14 | -6 |
| 15 | -12 |
| 16 | -20 |
| 17 | -20 |
| 18 | -40 |
| 19 | -46 |
| 20 | -68 |
| 21 | -104 |
| 22 | -132 |
| 23 | -204 |
| 24 | -280 |
| 25 | -394 |
| 26 | -578 |
| 27 | -790 |
| 28 | -1154 |
| 29 | -1616 |
| 30 | -2294 |
| 31 | -3286 |
| 32 | -4614 |
| 33 | -6610 |
| 34 | -9340 |
| 35 | -13278 |
| 36 | -18878 |
| 37 | -26748 |
| 38 | -38060 |
| 39 | -53978 |
| 40 | -76684 |
| 41 | -108912 |
| 42 | -154600 |
| 43 | -219622 |
| 44 | -311812 |
| 45 | -442818 |
| 46 | -628866 |
| 47 | -892962 |
| 48 | -1268168 |