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 | 3 |
| 2 | 33 |
| 3 | 315 |
| 4 | 26163 |
| 5 | 235953 |
| 6 | 2125035 |
| 7 | 19129689 |
| 8 | 172180323 |
| 9 | 1549662273 |
| 10 | 13947078555 |
| 11 | 125524061289 |
| 12 | 1129717614483 |
| 13 | 10167461718993 |
| 14 | 91507165036875 |
| 15 | 823564514029689 |
| 16 | 7412080712360643 |
| 17 | 66708726669526113 |
| 18 | 600378540800575995 |
| 19 | 5403406869529706889 |
| 20 | 48630661832740930803 |