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 | 2 |
| 3 | -1 |
| 4 | 9 |
| 5 | -9 |
| 6 | 1 |
| 7 | 44 |
| 8 | -66 |
| 9 | 24 |
| 10 | -1 |
| 11 | 265 |
| 12 | -530 |
| 13 | 320 |
| 14 | -55 |
| 15 | 1 |
| 16 | 1854 |
| 17 | -4635 |
| 18 | 3940 |
| 19 | -1275 |
| 20 | 118 |
| 21 | -1 |
| 22 | 14833 |
| 23 | -44499 |
| 24 | 48825 |
| 25 | -23485 |
| 26 | 4571 |
| 27 | -245 |
| 28 | 1 |
| 29 | 133496 |
| 30 | -467236 |
| 31 | 628544 |
| 32 | -403270 |
| 33 | 123368 |
| 34 | -15400 |
| 35 | 500 |
| 36 | -1 |
| 37 | 1334961 |
| 38 | -5339844 |
| 39 | 8510376 |
| 40 | -6841674 |
| 41 | 2885694 |
| 42 | -598416 |
| 43 | 49914 |
| 44 | -1011 |
| 45 | 1 |
| 46 | 14684570 |
| 47 | -66080565 |
| 48 | 121759560 |
| 49 | -117782490 |
| 50 | 63630588 |
| 51 | -18808230 |
| 52 | 2752320 |
| 53 | -157785 |
| 54 | 2034 |
| 55 | -1 |