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 | 100 |
| 4 | 370 |
| 5 | 1251 |
| 6 | 4005 |
| 7 | 12150 |
| 8 | 35400 |
| 9 | 99365 |
| 10 | 270353 |
| 11 | 715025 |
| 12 | 1844650 |
| 13 | 4652075 |
| 14 | 11494605 |
| 15 | 27872056 |
| 16 | 66428295 |
| 17 | 155809600 |
| 18 | 360079225 |
| 19 | 820715820 |
| 20 | 1846583863 |
| 21 | 4104572975 |
| 22 | 9019869125 |
| 23 | 19608423750 |
| 24 | 42193733645 |
| 25 | 89917531549 |
| 26 | 189863358445 |
| 27 | 397401303850 |