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 | -5 |
| 3 | 14 |
| 4 | -41 |
| 5 | 122 |
| 6 | -365 |
| 7 | 1094 |
| 8 | -3281 |
| 9 | 9842 |
| 10 | -29525 |
| 11 | 88574 |
| 12 | -265721 |
| 13 | 797162 |
| 14 | -2391485 |
| 15 | 7174454 |
| 16 | -21523361 |
| 17 | 64570082 |
| 18 | -193710245 |
| 19 | 581130734 |
| 20 | -1743392201 |
| 21 | 5230176602 |
| 22 | -15690529805 |
| 23 | 47071589414 |
| 24 | -141214768241 |
| 25 | 423644304722 |
| 26 | -1270932914165 |
| 27 | 3812798742494 |
| 28 | -11438396227481 |
| 29 | 34315188682442 |