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 | 5 |
| 2 | 0 |
| 3 | 1 |
| 4 | -3 |
| 5 | 7 |
| 6 | -15 |
| 7 | 31 |
| 8 | -63 |
| 9 | 126 |
| 10 | -245 |
| 11 | 455 |
| 12 | -791 |
| 13 | 1253 |
| 14 | -1715 |
| 15 | 1715 |
| 16 | 0 |
| 17 | -6419 |
| 18 | 24157 |
| 19 | -67081 |
| 20 | 162925 |
| 21 | -364609 |
| 22 | 767977 |
| 23 | -1535953 |
| 24 | 2922679 |
| 25 | -5273325 |
| 26 | 8931521 |
| 27 | -13886641 |
| 28 | 18775981 |
| 29 | -18399241 |
| 30 | -2035799 |
| 31 | 79594559 |
| 32 | -300540195 |
| 33 | 855744647 |
| 34 | -2151510735 |
| 35 | 5025003039 |