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 | 0 |
| 1 | -3 |
| 2 | 12 |
| 3 | -81 |
| 4 | 558 |
| 5 | -4095 |
| 6 | 31074 |
| 7 | -241761 |
| 8 | 1915998 |
| 9 | -15403839 |
| 10 | 125264226 |
| 11 | -1028198769 |
| 12 | 8505440256 |
| 13 | -70821126339 |
| 14 | 593013903996 |
| 15 | -4989710564097 |
| 16 | 42162715062462 |
| 17 | -357607035133503 |
| 18 | 3043168538309586 |
| 19 | -25973801534610801 |
| 20 | 222282241838388288 |
| 21 | -1906876619917171299 |
| 22 | 16394307639893817516 |
| 23 | -141231930366941378721 |