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 | 0 |
| 1 | 0 |
| 2 | 1 |
| 3 | 1 |
| 4 | 5 |
| 5 | 5 |
| 6 | 21 |
| 7 | 21 |
| 8 | 84 |
| 9 | 84 |
| 10 | 330 |
| 11 | 330 |
| 12 | 1287 |
| 13 | 1287 |
| 14 | 5005 |
| 15 | 5005 |
| 16 | 19448 |
| 17 | 19448 |
| 18 | 75582 |
| 19 | 75582 |
| 20 | 293930 |
| 21 | 293930 |
| 22 | 1144066 |
| 23 | 1144066 |
| 24 | 4457400 |
| 25 | 4457400 |
| 26 | 17383860 |
| 27 | 17383860 |
| 28 | 67863915 |
| 29 | 67863915 |
| 30 | 265182525 |