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 | 1 |
| 1 | 5 |
| 2 | 25 |
| 3 | 125 |
| 4 | 621 |
| 5 | 3065 |
| 6 | 15051 |
| 7 | 73645 |
| 8 | 359485 |
| 9 | 1752125 |
| 10 | 8532591 |
| 11 | 41537105 |
| 12 | 202200415 |
| 13 | 984526275 |
| 14 | 4795673085 |
| 15 | 23372376525 |
| 16 | 113978687085 |
| 17 | 556205251325 |
| 18 | 2716129289775 |
| 19 | 13273197773125 |
| 20 | 64909884686595 |
| 21 | 317652752793975 |
| 22 | 1555587408645225 |
| 23 | 7623031579626625 |