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 | -4 |
| 5 | 3 |
| 6 | 1 |
| 7 | -9 |
| 8 | 23 |
| 9 | -15 |
| 10 | 1 |
| 11 | -16 |
| 12 | 86 |
| 13 | -176 |
| 14 | 105 |
| 15 | 1 |
| 16 | -25 |
| 17 | 230 |
| 18 | -950 |
| 19 | 1689 |
| 20 | -945 |
| 21 | 1 |
| 22 | -36 |
| 23 | 505 |
| 24 | -3480 |
| 25 | 12139 |
| 26 | -19524 |
| 27 | 10395 |
| 28 | 1 |
| 29 | -49 |
| 30 | 973 |
| 31 | -10045 |
| 32 | 57379 |
| 33 | -177331 |
| 34 | 264207 |
| 35 | -135135 |
| 36 | 1 |
| 37 | -64 |
| 38 | 1708 |
| 39 | -24640 |
| 40 | 208054 |
| 41 | -1038016 |
| 42 | 2924172 |
| 43 | -4098240 |
| 44 | 2027025 |
| 45 | 1 |
| 46 | -81 |
| 47 | 2796 |
| 48 | -53676 |
| 49 | 626934 |
| 50 | -4574934 |
| 51 | 20570444 |
| 52 | -53809164 |
| 53 | 71697105 |
| 54 | -34459425 |