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 | 2 |
| 2 | 10 |
| 3 | 150 |
| 4 | 7650 |
| 5 | 1438200 |
| 6 | 1051324200 |
| 7 | 3101406390000 |
| 8 | 37945707181650000 |
| 9 | 1966422437567466300000 |
| 10 | 438887790263120370963300000 |
| 11 | 427664112802721593716655529100000 |