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 | 4 |
| 2 | 15 |
| 3 | 609 |
| 4 | 845029 |
| 5 | 1010073215739 |
| 6 | 1300459886313272270974271 |
| 7 | 1939680952094609786557359582286462958434022504402 |