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 | 21 |
| 2 | 454 |
| 3 | 9926 |
| 4 | 218838 |
| 5 | 4775307 |
| 6 | 104434119 |
| 7 | 2284814260 |
| 8 | 49979133672 |
| 9 | 1093274545336 |
| 10 | 23915155162485 |
| 11 | 523138192294728 |
| 12 | 11443519356879492 |
| 13 | 250324199629970283 |
| 14 | 5475780830828522030 |
| 15 | 119781370244825665556 |