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 | 0 |
| 2 | -127 |
| 3 | -2186 |
| 4 | -16383 |
| 5 | -78124 |
| 6 | -279935 |
| 7 | -823542 |
| 8 | -2097151 |
| 9 | -4782968 |
| 10 | -9999999 |
| 11 | -19487170 |
| 12 | -35831807 |
| 13 | -62748516 |
| 14 | -105413503 |
| 15 | -170859374 |
| 16 | -268435455 |
| 17 | -410338672 |
| 18 | -612220031 |
| 19 | -893871738 |
| 20 | -1279999999 |