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 | 2 |
| 3 | 4 |
| 4 | 25 |
| 5 | 217 |
| 6 | 203 |
| 7 | 6743 |
| 8 | 69511 |
| 9 | 1184417 |
| 10 | 728102 |
| 11 | 5720654791 |
| 12 | 601499 |
| 13 | 4670663321629 |
| 14 | 42568060798 |
| 15 | 888330615353 |
| 16 | 15438515749903 |
| 17 | 1676770323947695709 |
| 18 | 30538296012677 |
| 19 | 16858207434636875406943 |