Problem 115

Counting block combinations II

NOTE: This is a more difficult version of problem 114.

A row measuring *n* units in length has red blocks with a minimum length of *m*
units placed on it, such that any two red blocks (which are allowed to
be different lengths) are separated by at least one black square.

Let the fill-count function, F(*m*, *n*), represent the number of ways that a row can be filled.

For example, F(3, 29) = 673135 and F(3, 30) = 1089155.

That is, for *m* = 3, it can be seen that *n* = 30 is the smallest value for which the fill-count function first exceeds one million.

In the same way, for *m* = 10, it can be verified that F(10, 56) = 880711 and F(10, 57) = 1148904, so *n* = 57 is the least value for which the fill-count function first exceeds one million.

For *m* = 50, find the least value of *n* for which the fill-count function first exceeds one million.

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These problems are part of
Project Euler
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