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 | 1 |
| 4 | -3 |
| 5 | 2 |
| 6 | 1 |
| 7 | -8 |
| 8 | 17 |
| 9 | -10 |
| 10 | 1 |
| 11 | -22 |
| 12 | 129 |
| 13 | -248 |
| 14 | 140 |
| 15 | 1 |
| 16 | -64 |
| 17 | 1053 |
| 18 | -5666 |
| 19 | 10556 |
| 20 | -5880 |
| 21 | 1 |
| 22 | -196 |
| 23 | 9501 |
| 24 | -144662 |
| 25 | 758468 |
| 26 | -1399272 |
| 27 | 776160 |
| 28 | 1 |
| 29 | -625 |
| 30 | 93585 |
| 31 | -4220591 |
| 32 | 62818466 |
| 33 | -326782044 |
| 34 | 601063848 |
| 35 | -332972640 |
| 36 | 1 |
| 37 | -2055 |
| 38 | 987335 |
| 39 | -138047141 |
| 40 | 6098263596 |
| 41 | -90157188424 |
| 42 | 467899386768 |