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 | 17 |
| 2 | 87 |
| 3 | 437 |
| 4 | 2187 |
| 5 | 10937 |
| 6 | 54687 |
| 7 | 273437 |
| 8 | 1367187 |
| 9 | 6835937 |
| 10 | 34179687 |
| 11 | 170898437 |
| 12 | 854492187 |
| 13 | 4272460937 |
| 14 | 21362304687 |
| 15 | 106811523437 |
| 16 | 534057617187 |
| 17 | 2670288085937 |
| 18 | 13351440429687 |
| 19 | 66757202148437 |
| 20 | 333786010742187 |
| 21 | 1668930053710937 |