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 | 0 |
| 2 | -8 |
| 3 | 0 |
| 4 | 0 |
| 5 | -2048 |
| 6 | 0 |
| 7 | 192 |
| 8 | 16384 |
| 9 | 28311552 |
| 10 | 0 |
| 11 | 0 |
| 12 | -1179648 |
| 13 | 0 |
| 14 | 29686813949952 |
| 15 | 0 |
| 16 | -7680 |
| 17 | 67108864 |
| 18 | -289910292480 |
| 19 | 5699868278390784 |
| 20 | -3039929748475084800000 |
| 21 | 0 |
| 22 | 0 |
| 23 | -838860800 |
| 24 | 0 |
| 25 | 1094374709451030528 |
| 26 | 0 |
| 27 | -37180135792929290696471347200000 |
| 28 | 0 |