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 | 2 |
| 1 | -7 |
| 2 | 20 |
| 3 | -53 |
| 4 | 136 |
| 5 | -341 |
| 6 | 836 |
| 7 | -2005 |
| 8 | 4712 |
| 9 | -10881 |
| 10 | 24770 |
| 11 | -55763 |
| 12 | 124464 |
| 13 | -275933 |
| 14 | 608282 |
| 15 | -1334119 |
| 16 | 2911870 |
| 17 | -6325091 |
| 18 | 13674120 |
| 19 | -29425307 |
| 20 | 63042232 |
| 21 | -134517425 |
| 22 | 285984130 |
| 23 | -606056545 |
| 24 | 1280778342 |
| 25 | -2700105565 |
| 26 | 5680099084 |
| 27 | -11925792491 |