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 | -6 |
| 4 | 14 |
| 5 | -20 |
| 6 | 32 |
| 7 | -60 |
| 8 | 98 |
| 9 | -150 |
| 10 | 232 |
| 11 | -360 |
| 12 | 558 |
| 13 | -828 |
| 14 | 1196 |
| 15 | -1776 |
| 16 | 2614 |
| 17 | -3700 |
| 18 | 5238 |
| 19 | -7480 |
| 20 | 10516 |
| 21 | -14592 |
| 22 | 20180 |
| 23 | -27832 |
| 24 | 38216 |
| 25 | -51970 |
| 26 | 70184 |
| 27 | -94842 |
| 28 | 127612 |
| 29 | -170140 |
| 30 | 226164 |
| 31 | -300324 |
| 32 | 396754 |
| 33 | -521520 |
| 34 | 683484 |
| 35 | -893432 |
| 36 | 1164330 |
| 37 | -1511188 |
| 38 | 1954756 |
| 39 | -2524188 |