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 | 5 |
| 1 | 25 |
| 2 | 105 |
| 3 | 425 |
| 4 | 1705 |
| 5 | 6825 |
| 6 | 27305 |
| 7 | 109225 |
| 8 | 436905 |
| 9 | 1747625 |
| 10 | 6990505 |
| 11 | 27962025 |
| 12 | 111848105 |
| 13 | 447392425 |
| 14 | 1789569705 |
| 15 | 7158278825 |
| 16 | 28633115305 |
| 17 | 114532461225 |
| 18 | 458129844905 |
| 19 | 1832519379625 |
| 20 | 7330077518505 |
| 21 | 29320310074025 |