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 | 15 |
| 1 | 31 |
| 2 | 945 |
| 3 | 1921 |
| 4 | 58575 |
| 5 | 119071 |
| 6 | 3630705 |
| 7 | 7380481 |
| 8 | 225045135 |
| 9 | 457470751 |
| 10 | 13949167665 |
| 11 | 28355806081 |
| 12 | 864623350095 |
| 13 | 1757602506271 |
| 14 | 53592698538225 |
| 15 | 108942999582721 |
| 16 | 3321882686019855 |
| 17 | 6752708371622431 |
| 18 | 205903133834692785 |
| 19 | 418558976041008001 |
| 20 | 12762672415064932815 |