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 | 0 |
| 2 | -4 |
| 3 | -16 |
| 4 | -48 |
| 5 | -128 |
| 6 | -320 |
| 7 | -768 |
| 8 | -1792 |
| 9 | -4096 |
| 10 | -9216 |
| 11 | -20480 |
| 12 | -45056 |
| 13 | -98304 |
| 14 | -212992 |
| 15 | -458752 |
| 16 | -983040 |
| 17 | -2097152 |
| 18 | -4456448 |
| 19 | -9437184 |
| 20 | -19922944 |
| 21 | -41943040 |
| 22 | -88080384 |
| 23 | -184549376 |
| 24 | -385875968 |
| 25 | -805306368 |
| 26 | -1677721600 |
| 27 | -3489660928 |