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) |
|---|---|
| 0 | 3 |
| 1 | 15 |
| 2 | 171 |
| 3 | 2199 |
| 4 | 28563 |
| 5 | 371295 |
| 6 | 4826811 |
| 7 | 62748519 |
| 8 | 815730723 |
| 9 | 10604499375 |
| 10 | 137858491851 |
| 11 | 1792160394039 |
| 12 | 23298085122483 |
| 13 | 302875106592255 |
| 14 | 3937376385699291 |
| 15 | 51185893014090759 |
| 16 | 665416609183179843 |
| 17 | 8650415919381337935 |
| 18 | 112455406951957393131 |
| 19 | 1461920290375446110679 |