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 | 2 |
| 2 | -4 |
| 3 | 1 |
| 4 | 16 |
| 5 | -64 |
| 6 | 56 |
| 7 | -16 |
| 8 | 1 |
| 9 | 4096 |
| 10 | -32768 |
| 11 | 75776 |
| 12 | -77824 |
| 13 | 39296 |
| 14 | -9728 |
| 15 | 1184 |
| 16 | -64 |
| 17 | 1 |
| 18 | 4294967296 |
| 19 | -68719476736 |
| 20 | 375809638400 |
| 21 | -1043677052928 |
| 22 | 1696981843968 |
| 23 | -1726845288448 |
| 24 | 1143073669120 |
| 25 | -506453819392 |
| 26 | 152912134144 |
| 27 | -31653363712 |