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 | -1 |
| 2 | 0 |
| 3 | 27 |
| 4 | -416 |
| 5 | 5625 |
| 6 | -74304 |
| 7 | 924385 |
| 8 | -8626176 |
| 9 | -48361131 |
| 10 | 7124800000 |
| 11 | -340421390199 |
| 12 | 13686496542720 |
| 13 | -522760216822129 |
| 14 | 19658830846298112 |
| 15 | -735037915447265625 |
| 16 | 27218267709730979840 |
| 17 | -980444996625142158435 |
| 18 | 32830565919734078521344 |
| 19 | -889052809376495994642527 |