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 | 1 |
| 2 | 4 |
| 3 | 15 |
| 4 | 55 |
| 5 | 200 |
| 6 | 725 |
| 7 | 2625 |
| 8 | 9500 |
| 9 | 34375 |
| 10 | 124375 |
| 11 | 450000 |
| 12 | 1628125 |
| 13 | 5890625 |
| 14 | 21312500 |
| 15 | 77109375 |
| 16 | 278984375 |
| 17 | 1009375000 |
| 18 | 3651953125 |
| 19 | 13212890625 |
| 20 | 47804687500 |
| 21 | 172958984375 |
| 22 | 625771484375 |
| 23 | 2264062500000 |
| 24 | 8191455078125 |