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 | -4 |
| 5 | 1 |
| 6 | 9 |
| 7 | -44 |
| 8 | 42 |
| 9 | -12 |
| 10 | 1 |
| 11 | 272 |
| 12 | -3712 |
| 13 | 11648 |
| 14 | -14208 |
| 15 | 8256 |
| 16 | -2496 |
| 17 | 400 |
| 18 | -32 |
| 19 | 1 |
| 20 | 589185 |
| 21 | -25108944 |
| 22 | 259084440 |
| 23 | -1129177840 |
| 24 | 2605908220 |
| 25 | -3594554960 |
| 26 | 3190117800 |
| 27 | -1910146160 |
| 28 | 795862790 |
| 29 | -235146480 |
| 30 | 49715240 |
| 31 | -7517264 |
| 32 | 803580 |
| 33 | -59120 |
| 34 | 2840 |
| 35 | -80 |
| 36 | 1 |
| 37 | 16332454526976 |
| 38 | -2333280165691392 |
| 39 | 81808261704974336 |