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) |
|---|---|
| 0 | 1 |
| 1 | -2 |
| 2 | 4 |
| 3 | -7 |
| 4 | 13 |
| 5 | -23 |
| 6 | 42 |
| 7 | -75 |
| 8 | 136 |
| 9 | -244 |
| 10 | 441 |
| 11 | -793 |
| 12 | 1431 |
| 13 | -2576 |
| 14 | 4645 |
| 15 | -8366 |
| 16 | 15080 |
| 17 | -27167 |
| 18 | 48961 |
| 19 | -88215 |
| 20 | 158970 |
| 21 | -286439 |
| 22 | 516164 |
| 23 | -930072 |
| 24 | 1675961 |
| 25 | -3019941 |
| 26 | 5441791 |
| 27 | -9805712 |
| 28 | 17669353 |
| 29 | -31838986 |
| 30 | 57371980 |
| 31 | -103380599 |
| 32 | 186285573 |
| 33 | -335674791 |
| 34 | 604865338 |
| 35 | -1089929347 |
| 36 | 1963985232 |