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 | 4 |
| 3 | -6 |
| 4 | 8 |
| 5 | -12 |
| 6 | 18 |
| 7 | -24 |
| 8 | 32 |
| 9 | -44 |
| 10 | 58 |
| 11 | -76 |
| 12 | 100 |
| 13 | -128 |
| 14 | 164 |
| 15 | -210 |
| 16 | 264 |
| 17 | -332 |
| 18 | 416 |
| 19 | -516 |
| 20 | 640 |
| 21 | -790 |
| 22 | 968 |
| 23 | -1184 |
| 24 | 1444 |
| 25 | -1752 |
| 26 | 2120 |
| 27 | -2560 |
| 28 | 3078 |
| 29 | -3692 |
| 30 | 4420 |
| 31 | -5272 |
| 32 | 6276 |
| 33 | -7456 |
| 34 | 8832 |
| 35 | -10444 |
| 36 | 12326 |
| 37 | -14512 |
| 38 | 17056 |
| 39 | -20012 |
| 40 | 23432 |
| 41 | -27392 |
| 42 | 31972 |
| 43 | -37248 |
| 44 | 43332 |
| 45 | -50338 |
| 46 | 58380 |
| 47 | -67616 |
| 48 | 78208 |
| 49 | -90328 |
| 50 | 104196 |