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) |
|---|---|
| 1 | 1 |
| 2 | -1 |
| 3 | -2 |
| 4 | 0 |
| 5 | 4 |
| 6 | -4 |
| 7 | -6 |
| 8 | 0 |
| 9 | 0 |
| 10 | -16 |
| 11 | -10 |
| 12 | 0 |
| 13 | 12 |
| 14 | -36 |
| 15 | -2048 |
| 16 | 0 |
| 17 | 16 |
| 18 | 0 |
| 19 | -18 |
| 20 | 0 |
| 21 | 27648 |
| 22 | -100 |
| 23 | -22 |
| 24 | 0 |
| 25 | 0 |
| 26 | -144 |
| 27 | 0 |
| 28 | 0 |
| 29 | 28 |
| 30 | -4194304 |
| 31 | -30 |
| 32 | 0 |
| 33 | 2048000 |
| 34 | -256 |
| 35 | -127401984 |
| 36 | 0 |
| 37 | 36 |
| 38 | -324 |
| 39 | -14155776 |
| 40 | 0 |
| 41 | 40 |
| 42 | -764411904 |
| 43 | -42 |
| 44 | 0 |
| 45 | 0 |
| 46 | -484 |
| 47 | -46 |
| 48 | 0 |
| 49 | 0 |
| 50 | 0 |
| 51 | -536870912 |
| 52 | 0 |
| 53 | 52 |
| 54 | 0 |
| 55 | -419430400000 |
| 56 | 0 |
| 57 | 3057647616 |
| 58 | -784 |
| 59 | -58 |
| 60 | 0 |