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 | -4 |
| 4 | 6 |
| 5 | -8 |
| 6 | 12 |
| 7 | -16 |
| 8 | 22 |
| 9 | -30 |
| 10 | 40 |
| 11 | -52 |
| 12 | 68 |
| 13 | -88 |
| 14 | 112 |
| 15 | -144 |
| 16 | 182 |
| 17 | -228 |
| 18 | 286 |
| 19 | -356 |
| 20 | 440 |
| 21 | -544 |
| 22 | 668 |
| 23 | -816 |
| 24 | 996 |
| 25 | -1210 |
| 26 | 1464 |
| 27 | -1768 |
| 28 | 2128 |
| 29 | -2552 |
| 30 | 3056 |
| 31 | -3648 |
| 32 | 4342 |
| 33 | -5160 |
| 34 | 6116 |
| 35 | -7232 |
| 36 | 8538 |
| 37 | -10056 |
| 38 | 11820 |
| 39 | -13872 |
| 40 | 16248 |
| 41 | -18996 |
| 42 | 22176 |
| 43 | -25844 |
| 44 | 30068 |
| 45 | -34936 |
| 46 | 40528 |