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 | -3 |
| 1 | 11 |
| 2 | -30 |
| 3 | 79 |
| 4 | -207 |
| 5 | 542 |
| 6 | -1419 |
| 7 | 3715 |
| 8 | -9726 |
| 9 | 25463 |
| 10 | -66663 |
| 11 | 174526 |
| 12 | -456915 |
| 13 | 1196219 |
| 14 | -3131742 |
| 15 | 8199007 |
| 16 | -21465279 |
| 17 | 56196830 |
| 18 | -147125211 |
| 19 | 385178803 |
| 20 | -1008411198 |
| 21 | 2640054791 |
| 22 | -6911753175 |
| 23 | 18095204734 |
| 24 | -47373861027 |
| 25 | 124026378347 |
| 26 | -324705274014 |
| 27 | 850089443695 |
| 28 | -2225563057071 |
| 29 | 5826599727518 |
| 30 | -15254236125483 |