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 | 2 |
| 2 | 135 |
| 3 | 735 |
| 4 | 21372 |
| 5 | 271362 |
| 6 | 4773132 |
| 7 | 113678565 |
| 8 | 11317129824 |
| 9 | 131175822960 |
| 10 | 7113719552940 |
| 11 | 255360234137190 |
| 12 | 12411792985131540 |