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 | -1 |
| 2 | 2 |
| 3 | -2 |
| 4 | 2 |
| 5 | 0 |
| 6 | -4 |
| 7 | 12 |
| 8 | -22 |
| 9 | 34 |
| 10 | -42 |
| 11 | 38 |
| 12 | -6 |
| 13 | -68 |
| 14 | 202 |
| 15 | -394 |
| 16 | 616 |
| 17 | -782 |
| 18 | 730 |
| 19 | -204 |
| 20 | -1104 |
| 21 | 3486 |
| 22 | -6994 |
| 23 | 11142 |
| 24 | -14452 |
| 25 | 14026 |
| 26 | -5296 |
| 27 | -17558 |
| 28 | 60042 |
| 29 | -123860 |
| 30 | 201128 |
| 31 | -266384 |
| 32 | 268176 |
| 33 | -124034 |
| 34 | -273626 |
| 35 | 1030396 |
| 36 | -2188864 |
| 37 | 3624290 |
| 38 | -4898740 |
| 39 | 5101306 |
| 40 | -2744408 |