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 | -1 |
| 2 | 1 |
| 3 | 4 |
| 4 | -5 |
| 5 | 1 |
| 6 | -22 |
| 7 | 30 |
| 8 | -9 |
| 9 | 1 |
| 10 | 140 |
| 11 | -200 |
| 12 | 72 |
| 13 | -13 |
| 14 | 1 |
| 15 | -969 |
| 16 | 1425 |
| 17 | -570 |
| 18 | 130 |
| 19 | -17 |
| 20 | 1 |
| 21 | 7084 |
| 22 | -10626 |
| 23 | 4554 |
| 24 | -1196 |
| 25 | 204 |
| 26 | -21 |
| 27 | 1 |
| 28 | -53820 |
| 29 | 81900 |
| 30 | -36855 |
| 31 | 10647 |
| 32 | -2142 |
| 33 | 294 |
| 34 | -25 |
| 35 | 1 |
| 36 | 420732 |
| 37 | -647280 |
| 38 | 302064 |
| 39 | -93496 |
| 40 | 21080 |
| 41 | -3472 |
| 42 | 400 |
| 43 | -29 |
| 44 | 1 |
| 45 | -3362260 |
| 46 | 5217300 |
| 47 | -2504304 |
| 48 | 816816 |
| 49 | -200277 |
| 50 | 37485 |
| 51 | -5250 |
| 52 | 522 |