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 | 0 |
| 2 | 10 |
| 3 | 50 |
| 4 | 150 |
| 5 | 1014 |
| 6 | 9450 |
| 7 | 8305 |
| 8 | 283055 |
| 9 | 931395 |
| 10 | 92441055 |
| 11 | 84305555 |
| 12 | 28322235955 |