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 | 4 |
| 1 | 9 |
| 2 | 84 |
| 3 | 11142 |
| 4 | 474347339 |
| 5 | 1448582974451426406 |
| 6 | 2526762018809024624337804813995389534 |
| 7 | 28249016389028465904997590221278194109894254535234000317524709009386354668 |