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 | 5 |
| 2 | 25 |
| 3 | 125 |
| 4 | 623 |
| 5 | 3094 |
| 6 | 15365 |
| 7 | 76300 |
| 8 | 378880 |
| 9 | 1881364 |
| 10 | 9342081 |
| 11 | 46388915 |
| 12 | 230348138 |
| 13 | 1143813376 |
| 14 | 5679703079 |
| 15 | 28203050974 |
| 16 | 140044659409 |
| 17 | 695403722139 |
| 18 | 3453086599482 |
| 19 | 17146596550508 |
| 20 | 85142890221146 |
| 21 | 422784296221329 |