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 | -3 |
| 5 | 10 |
| 6 | 18 |
| 7 | -68 |
| 8 | -131 |
| 9 | 530 |
| 10 | 1062 |
| 11 | -4476 |
| 12 | -9198 |
| 13 | 39844 |
| 14 | 83332 |
| 15 | -368136 |
| 16 | -780003 |
| 17 | 3497058 |
| 18 | 7483806 |
| 19 | -33940940 |
| 20 | -73210874 |
| 21 | 335103340 |
| 22 | 727473084 |
| 23 | -3355045304 |
| 24 | -7322240718 |
| 25 | 33982884884 |
| 26 | 74498594492 |
| 27 | -347600543192 |
| 28 | -764936992764 |
| 29 | 3585459509640 |
| 30 | 7916276980872 |
| 31 | -37253166379536 |