Number of nX2 0..4 arrays with some element plus some horizontally or vertically adjacent neighbor totalling four exactly once.
A270052
Number of nX2 0..4 arrays with some element plus some horizontally or vertically adjacent neighbor totalling four exactly once.
Terms
- a(0) =5a(1) =240a(2) =5400a(3) =99840a(4) =1683240a(5) =26891280a(6) =414705720a(7) =6237722400a(8) =92095515720
External references
- oeis: A270052