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 | 0 |
| 1 | -1 |
| 2 | 2 |
| 3 | -5 |
| 4 | 6 |
| 5 | -13 |
| 6 | 10 |
| 7 | -29 |
| 8 | 6 |
| 9 | -69 |
| 10 | -38 |
| 11 | -197 |
| 12 | -250 |
| 13 | -669 |
| 14 | -1142 |
| 15 | -2509 |
| 16 | -4762 |
| 17 | -9813 |
| 18 | -19302 |
| 19 | -38965 |
| 20 | -77530 |
| 21 | -155501 |
| 22 | -310518 |
| 23 | -621565 |
| 24 | -1242554 |
| 25 | -2485733 |
| 26 | -4970790 |
| 27 | -9942309 |
| 28 | -19883834 |
| 29 | -39768509 |
| 30 | -79536118 |