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PROJECT EULER · #0813

XOR-Powers

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We use xy to be the bitwise XOR of x and y.

Define the XOR-product of x and y, denoted by xy, similar to a long multiplication in base 2, except that the intermediate results are XORed instead of the usual integer addition.

For example, 1111=69, or in base 2, 1011210112=10001012:

1111101121111101121111101121111011291101129991110001012 Further we define P(n)=11n=111111n. For example P(2)=69.

Find P(812128). Give your answer modulo 109+7.

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