Project Euler > Problem 167 > Investigating Ulam sequences (Java Solution)

Problem:

For two positive integers a and b, the Ulam sequence U(a,b) is defined by U(a,b)1 = a, U(a,b)2 = b and for k > 2, U(a,b)k is the smallest integer greater than U(a,b)(k-1) which can be written in exactly one way as the sum of two distinct previous members of U(a,b).

For example, the sequence U(1,2) begins with
1, 2, 3 = 1 + 2, 4 = 1 + 3, 6 = 2 + 4, 8 = 2 + 6, 11 = 3 + 8;
5 does not belong to it because 5 = 1 + 4 = 2 + 3 has two representations as the sum of two previous members, likewise 7 = 1 + 6 = 3 + 4.

Find [∑]U(2,2n+1)k for 2 [≤] n [≤]10, where k = 1011.

Solution:

21124

Code:
The solution may include methods that will be found here: Library.java .

public interface EulerSolution{

public String run();

}

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