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 | 1 |
| 2 | 3 |
| 3 | 11 |
| 4 | 47 |
| 5 | 241 |
| 6 | 1457 |
| 7 | 10223 |
| 8 | 81835 |
| 9 | 736637 |
| 10 | 7366661 |
| 11 | 81034027 |
| 12 | 972410303 |
| 13 | 12641339465 |
| 14 | 176978768137 |
| 15 | 2654681568551 |
| 16 | 42474905237267 |
| 17 | 722073389475733 |
| 18 | 12997321011978125 |
| 19 | 246949099232271587 |
| 20 | 4938981984661217191 |