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 | 5 |
| 3 | 17 |
| 4 | 257 |
| 5 | 46657 |
| 6 | 65537 |
| 7 | 148997 |
| 8 | 67371265 |
| 9 | 405458497 |
| 10 | 1370776577 |
| 11 | 3497539601 |
| 12 | 4294967297 |
| 13 | 80542440001 |
| 14 | 422240040001 |
| 15 | 1911029760001 |
| 16 | 139251776898727937 |
| 17 | 286245437364810001 |
| 18 | 6017402415698251777 |
| 19 | 18446744073709551617 |