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 | -9 |
| 2 | 109 |
| 3 | -63 |
| 4 | 1051 |
| 5 | -357 |
| 6 | 27973 |
| 7 | -3423 |
| 8 | 93571 |
| 9 | 42903 |
| 10 | -37758991 |
| 11 | -3856083 |
| 12 | 27354236881 |
| 13 | 375324963 |
| 14 | -34558569101 |
| 15 | -49956225543 |
| 16 | 89299360103987 |
| 17 | 8604861227823 |
| 18 | -135379634123142593 |
| 19 | -1863607938895803 |
| 20 | 2694379431784131041 |
| 21 | 495661415733687483 |
| 22 | -1648224141815965152043 |