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 | 2 |
| 2 | -10 |
| 3 | 110 |
| 4 | -1430 |
| 5 | 20570 |
| 6 | -315282 |
| 7 | 5047350 |
| 8 | -83406510 |
| 9 | 1411954610 |
| 10 | -24360750810 |
| 11 | 426796726334 |
| 12 | -7572551327430 |
| 13 | 135790011411850 |
| 14 | -2457028916693090 |
| 15 | 44804882306441990 |
| 16 | -822573909558939998 |
| 17 | 15191515999168557410 |
| 18 | -282038057756813698730 |