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 | -5 |
| 4 | -13 |
| 5 | -37 |
| 6 | -83 |
| 7 | -194 |
| 8 | -469 |
| 9 | -1111 |
| 10 | -2743 |
| 11 | -6698 |
| 12 | -16379 |
| 13 | -40543 |
| 14 | -101251 |
| 15 | -254053 |
| 16 | -640483 |
| 17 | -1622840 |
| 18 | -4133371 |
| 19 | -10578367 |
| 20 | -27130829 |
| 21 | -69814219 |