A069401 Half the number of 8 X n binary arrays with a path of adjacent 1's and a path of adjacent 0's from top row to bottom row.
1, 3193, 3625675, 2522968803
Offset: 2
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.