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) |
|---|---|
| 3 | 0 |
| 4 | 139 |
| 5 | 1751 |
| 6 | 187243 |
| 7 | 16777215 |
| 8 | 33554571 |
| 9 | 50333399 |
| 10 | 84073323 |
| 11 | 134217727 |
| 12 | 134217867 |
| 13 | 134219479 |
| 14 | 134404971 |
| 15 | 150994943 |