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 | 0 |
| 2 | 1 |
| 3 | 0 |
| 4 | -1 |
| 5 | 2 |
| 6 | 0 |
| 7 | 5 |
| 8 | -12 |
| 9 | 8 |
| 10 | 0 |
| 11 | -79 |
| 12 | 208 |
| 13 | -192 |
| 14 | 64 |
| 15 | 0 |
| 16 | 3377 |
| 17 | -9520 |
| 18 | 10240 |
| 19 | -5120 |
| 20 | 1024 |
| 21 | 0 |
| 22 | -362431 |
| 23 | 1079744 |
| 24 | -1282560 |
| 25 | 778240 |
| 26 | -245760 |
| 27 | 32768 |
| 28 | 0 |
| 29 | 93473345 |
| 30 | -291615296 |
| 31 | 372893696 |
| 32 | -255754240 |
| 33 | 100925440 |
| 34 | -22020096 |
| 35 | 2097152 |
| 36 | 0 |
| 37 | -56272471039 |
| 38 | 182582658048 |
| 39 | -247557029888 |
| 40 | 185511968768 |
| 41 | -84263567360 |
| 42 | 23488102400 |
| 43 | -3758096384 |
| 44 | 268435456 |