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 | -7 |
| 2 | 14 |
| 3 | -7 |
| 4 | 0 |
| 5 | 0 |
| 6 | 0 |
| 7 | -1 |
| 8 | -7 |
| 9 | -35 |
| 10 | -154 |
| 11 | -637 |
| 12 | -2548 |
| 13 | -9996 |
| 14 | -38760 |
| 15 | -149226 |
| 16 | -572033 |
| 17 | -2187185 |
| 18 | -8351070 |
| 19 | -31865925 |
| 20 | -121580760 |
| 21 | -463991880 |
| 22 | -1771605360 |
| 23 | -6768687870 |
| 24 | -25880277150 |
| 25 | -99035193894 |
| 26 | -379300783092 |
| 27 | -1453986335186 |
| 28 | -5578559816632 |
| 29 | -21422369201800 |