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) |
|---|---|
| 1 | 2 |
| 2 | 0 |
| 3 | 0 |
| 4 | 2 |
| 5 | -4 |
| 6 | 8 |
| 7 | -16 |
| 8 | 32 |
| 9 | -54 |
| 10 | 108 |
| 11 | -184 |
| 12 | 368 |
| 13 | -628 |
| 14 | 1296 |
| 15 | -2160 |
| 16 | 4610 |
| 17 | -7708 |
| 18 | 15848 |
| 19 | -27592 |
| 20 | 58316 |
| 21 | -98496 |
| 22 | 207576 |
| 23 | -364720 |
| 24 | 756872 |
| 25 | -1341970 |
| 26 | 2778300 |
| 27 | -4918536 |
| 28 | 10443152 |
| 29 | -18512788 |
| 30 | 37698416 |
| 31 | -69273664 |
| 32 | 145105952 |
| 33 | -258224544 |
| 34 | 534996900 |
| 35 | -981494752 |
| 36 | 2020011290 |
| 37 | -3714566308 |
| 38 | 7614288360 |