Number of permutations of {1,2,...,n} having no isolated fixed points. A fixed point j of a permutation is said to be isolated if neither j-1 nor j+1 is a fixed point. For example, 4135267 has only 3 as an isolated fixed point.

A184179

Number of permutations of {1,2,...,n} having no isolated fixed points. A fixed point j of a permutation is said to be isolated if neither j-1 nor j+1 is a fixed point. For example, 4135267 has only 3 as an isolated fixed point.