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 | 1 |
| 2 | -5 |
| 3 | -28 |
| 4 | 16 |
| 5 | -3126 |
| 6 | 47450 |
| 7 | -823544 |
| 8 | 0 |
| 9 | 19683 |
| 10 | 10009766650 |
| 11 | -285311670612 |
| 12 | -2176786432 |
| 13 | -302875106592254 |
| 14 | 11112685048647250 |
| 15 | 437893920912786408 |
| 16 | 0 |
| 17 | -827240261886336764178 |
| 18 | -101560344088905 |
| 19 | -1978419655660313589123980 |
| 20 | -100000000000001048576 |