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PROJECT EULER · #0553

Power Sets of Power Sets

Statement only · UnsolvedOriginal problem ↗

Let P(n) be the set of the first n positive integers {1,2,,n}.
Let Q(n) be the set of all the non-empty subsets of P(n).
Let R(n) be the set of all the non-empty subsets of Q(n).

An element XR(n) is a non-empty subset of Q(n), so it is itself a set.
From X we can construct a graph as follows:

  • Each element YX corresponds to a vertex and labeled with Y;
  • Two vertices Y1 and Y2 are connected if Y1Y2.

For example, X={{1},{1,2,3},{3},{5,6},{6,7}} results in the following graph:

0553-power-sets.gif

This graph has two connected components.

Let C(n,k) be the number of elements of R(n) that have exactly k connected components in their graph.
You are given C(2,1)=6, C(3,1)=111, C(4,2)=486, C(100,10)mod1000000007=728209718.

Find C(104,10)mod1000000007.

Write-up coming later

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