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 | 3 |
| 1 | 7 |
| 2 | 47 |
| 3 | 2207 |
| 4 | 4870847 |
| 5 | 23725150497407 |
| 6 | 562882766124611619513723647 |
| 7 | 316837008400094222150776738483768236006420971486980607 |