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) |
|---|---|
| 2 | 3 |
| 3 | 19 |
| 4 | 137 |
| 5 | 1289 |
| 6 | 16909 |
| 7 | 259087 |
| 8 | 4975049 |
| 9 | 106267661 |
| 10 | 2725447213 |
| 11 | 85953848147 |
| 12 | 2903947942067 |
| 13 | 115669053951809 |
| 14 | 5061522951820999 |
| 15 | 231945249314081827 |
| 16 | 11594813068340357459 |
| 17 | 650803589794759938517 |
| 18 | 40385350464999429101033 |