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 | 1 |
| 2 | 0 |
| 3 | -3 |
| 4 | -11 |
| 5 | -30 |
| 6 | -72 |
| 7 | -162 |
| 8 | -353 |
| 9 | -756 |
| 10 | -1598 |
| 11 | -3334 |
| 12 | -6868 |
| 13 | -14002 |
| 14 | -28368 |
| 15 | -57374 |
| 16 | -116233 |
| 17 | -236165 |
| 18 | -480781 |
| 19 | -978293 |
| 20 | -1984231 |
| 21 | -4003365 |
| 22 | -8028201 |
| 23 | -16011129 |
| 24 | -31812545 |
| 25 | -63129395 |
| 26 | -125452526 |
| 27 | -250216779 |
| 28 | -501567302 |