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 | -3 |
| 5 | 2 |
| 6 | 1 |
| 7 | -7 |
| 8 | 14 |
| 9 | -8 |
| 10 | 1 |
| 11 | -15 |
| 12 | 70 |
| 13 | -120 |
| 14 | 64 |
| 15 | 1 |
| 16 | -31 |
| 17 | 310 |
| 18 | -1240 |
| 19 | 1984 |
| 20 | -1024 |
| 21 | 1 |
| 22 | -63 |
| 23 | 1302 |
| 24 | -11160 |
| 25 | 41664 |
| 26 | -64512 |
| 27 | 32768 |
| 28 | 1 |
| 29 | -127 |
| 30 | 5334 |
| 31 | -94488 |
| 32 | 755904 |
| 33 | -2731008 |
| 34 | 4161536 |
| 35 | -2097152 |
| 36 | 1 |
| 37 | -255 |
| 38 | 21590 |
| 39 | -777240 |
| 40 | 12850368 |
| 41 | -99486720 |
| 42 | 353730560 |