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) |
|---|---|
| 20 | 1 |
| 21 | -20 |
| 22 | 190 |
| 23 | -1140 |
| 24 | 4825 |
| 25 | -15124 |
| 26 | 35320 |
| 27 | -57760 |
| 28 | 45220 |
| 29 | 80560 |
| 30 | -405954 |
| 31 | 910460 |
| 32 | -1289340 |
| 33 | 852340 |
| 34 | 1259530 |
| 35 | -5357924 |
| 36 | 10151510 |
| 37 | -12048660 |
| 38 | 5883350 |
| 39 | 12186960 |
| 40 | -40135713 |
| 41 | 66244280 |
| 42 | -69648870 |
| 43 | 28191460 |
| 44 | 66920755 |
| 45 | -195366168 |
| 46 | 300881530 |