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A077815

2^phi(n) mod n^2, where phi is Euler's totient function A000010.

0, 2, 4, 4, 16, 4, 15, 16, 64, 16, 56, 16, 40, 64, 31, 0, 222, 64, 58, 256, 127, 56, 392, 256, 451, 40, 433, 176, 30, 256, 187, 0, 958, 800, 841, 208, 38, 780, 586, 1536, 944, 568, 1076, 1200, 91, 392, 2069, 1024, 2157, 1076, 1021, 1600, 1909, 2620, 826, 2752

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OFFSET

1,2

LINKS

Harvey P. Dale, Table of n, a(n) for n = 1..1000

EXAMPLE

a(42) = 2^phi(42) mod 42*42 = 2^phi(2*3*7) mod 1764 = 2^(42*(1-1/2)*(1-1/3)*(1-1/7)) mod 1764 = 2^12 mod 1764 = 4096 mod 1764 = 568.

MATHEMATICA

PowerMod[2, EulerPhi[#], #^2]&/@Range[60] (* Harvey P. Dale, Dec 04 2021 *)

PROG

(PARI) a(n)=lift(Mod(2, n^2)^eulerphi(n)) \\ Charles R Greathouse IV, Feb 21 2013

CROSSREFS