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 | -6 |
| 3 | -28 |
| 4 | -26 |
| 5 | -156 |
| 6 | -476 |
| 7 | 968 |
| 8 | 11526 |
| 9 | -16172 |
| 10 | 139724 |
| 11 | 791928 |
| 12 | 1315548 |
| 13 | 12772840 |
| 14 | 31004424 |
| 15 | -105335920 |
| 16 | 1058225606 |
| 17 | 2239259700 |
| 18 | -3700870212 |
| 19 | 29301955992 |
| 20 | -4944685836 |
| 21 | -526686535112 |
| 22 | 1134044530040 |
| 23 | 4057865621232 |
| 24 | -13063873857124 |
| 25 | -113573062924024 |