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 | -7 |
| 2 | 21 |
| 3 | -42 |
| 4 | 84 |
| 5 | -175 |
| 6 | 322 |
| 7 | -547 |
| 8 | 931 |
| 9 | -1561 |
| 10 | 2527 |
| 11 | -3976 |
| 12 | 6167 |
| 13 | -9485 |
| 14 | 14336 |
| 15 | -21280 |
| 16 | 31304 |
| 17 | -45696 |
| 18 | 65940 |
| 19 | -94122 |
| 20 | 133371 |
| 21 | -187734 |
| 22 | 262143 |
| 23 | -363265 |
| 24 | 500381 |
| 25 | -685503 |
| 26 | 933506 |
| 27 | -1263794 |
| 28 | 1702590 |
| 29 | -2283379 |
| 30 | 3047597 |