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 | -1 |
| 3 | -5 |
| 4 | -11 |
| 5 | -119 |
| 6 | 241 |
| 7 | -5039 |
| 8 | -1679 |
| 9 | -60479 |
| 10 | 1784161 |
| 11 | -39916799 |
| 12 | 218877121 |
| 13 | -6227020799 |
| 14 | 43571848321 |
| 15 | 1078831353601 |
| 16 | -518918399 |
| 17 | -355687428095999 |
| 18 | 1058152455360001 |
| 19 | -121645100408831999 |
| 20 | 1115079416638387201 |
| 21 | 42565648051390464001 |
| 22 | 562000335730215782401 |