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 | 0 |
| 2 | 0 |
| 3 | 1 |
| 4 | 7 |
| 5 | 63 |
| 6 | 1023 |
| 7 | 32760 |
| 8 | 1048544 |
| 9 | 33554304 |
| 10 | 1073741312 |
| 11 | 34359736320 |
| 12 | 1099511619584 |
| 13 | 35184370221056 |
| 14 | 1125899873681408 |
| 15 | 36028796752101376 |