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 | -5 |
| 5 | 4 |
| 6 | 1 |
| 7 | -12 |
| 8 | 35 |
| 9 | -30 |
| 10 | 1 |
| 11 | -22 |
| 12 | 143 |
| 13 | -362 |
| 14 | 312 |
| 15 | 1 |
| 16 | -35 |
| 17 | 405 |
| 18 | -2065 |
| 19 | 4814 |
| 20 | -4200 |
| 21 | 1 |
| 22 | -51 |
| 23 | 925 |
| 24 | -7965 |
| 25 | 35434 |
| 26 | -78744 |
| 27 | 69120 |
| 28 | 1 |
| 29 | -70 |
| 30 | 1834 |
| 31 | -24010 |
| 32 | 173929 |
| 33 | -709240 |
| 34 | 1525236 |
| 35 | -1345680 |
| 36 | 1 |
| 37 | -92 |
| 38 | 3290 |
| 39 | -61040 |
| 40 | 655529 |
| 41 | -4235588 |
| 42 | 16255420 |
| 43 | -34148400 |
| 44 | 30240000 |