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 | 55 |
| 3 | 2055 |
| 4 | 291430 |
| 5 | 165397680 |
| 6 | 390075741430 |
| 7 | 3927972221522680 |
| 8 | 172358768282285194555 |
| 9 | 33479766506261422878944555 |
| 10 | 29150234311482124092454001991430 |