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 | 1 |
| 4 | -3 |
| 5 | 2 |
| 6 | 1 |
| 7 | -8 |
| 8 | 17 |
| 9 | -10 |
| 10 | 1 |
| 11 | -23 |
| 12 | 137 |
| 13 | -265 |
| 14 | 150 |
| 15 | 1 |
| 16 | -75 |
| 17 | 1333 |
| 18 | -7389 |
| 19 | 13930 |
| 20 | -7800 |
| 21 | 1 |
| 22 | -278 |
| 23 | 16558 |
| 24 | -277988 |
| 25 | 1513897 |
| 26 | -2835590 |
| 27 | 1583400 |
| 28 | 1 |
| 29 | -1155 |
| 30 | 260364 |
| 31 | -14799354 |
| 32 | 245309373 |
| 33 | -1330523259 |
| 34 | 2488395830 |
| 35 | -1388641800 |
| 36 | 1 |
| 37 | -5295 |
| 38 | 5042064 |
| 39 | -1092706314 |
| 40 | 61514634933 |
| 41 | -1016911327479 |