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 | 1 |
| 4 | 0 |
| 5 | -1 |
| 6 | 1 |
| 7 | 2 |
| 8 | -1 |
| 9 | -2 |
| 10 | 1 |
| 11 | -4 |
| 12 | -13 |
| 13 | 4 |
| 14 | 12 |
| 15 | 1 |
| 16 | 20 |
| 17 | -109 |
| 18 | -308 |
| 19 | 108 |
| 20 | 288 |
| 21 | 1 |
| 22 | -100 |
| 23 | -2509 |
| 24 | 12772 |
| 25 | 37068 |
| 26 | -12672 |
| 27 | -34560 |
| 28 | 1 |
| 29 | 620 |
| 30 | -74509 |
| 31 | -1793708 |
| 32 | 9232908 |
| 33 | 26676288 |
| 34 | -9158400 |
| 35 | -24883200 |
| 36 | 1 |
| 37 | -4420 |
| 38 | -3199309 |
| 39 | 373731652 |
| 40 | 9049521228 |
| 41 | -46507180032 |
| 42 | -134457649920 |
| 43 | 46133452800 |
| 44 | 125411328000 |