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 | 2 |
| 5 | 2 |
| 6 | -14 |
| 7 | -68 |
| 8 | -308 |
| 9 | -1178 |
| 10 | -4366 |
| 11 | -15772 |
| 12 | -56780 |
| 13 | -203916 |
| 14 | -734772 |
| 15 | -2658088 |
| 16 | -9662208 |
| 17 | -35292134 |
| 18 | -129514026 |
| 19 | -477376556 |
| 20 | -1766739436 |
| 21 | -6563071972 |
| 22 | -24464170892 |
| 23 | -91478369336 |
| 24 | -343051227304 |
| 25 | -1289887370136 |
| 26 | -4861912851116 |
| 27 | -18367285963792 |
| 28 | -69533416706328 |
| 29 | -263747683314904 |
| 30 | -1002241679797688 |