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A064448
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a(n) = gcd(n^n, EulerPhi(n^n)).
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1
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1, 2, 9, 128, 625, 15552, 117649, 8388608, 129140163, 2000000000, 25937424601, 2972033482752, 23298085122481, 1587429546508288, 29192926025390625, 9223372036854775808, 48661191875666868481, 13115469358432179191808
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OFFSET
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1,2
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LINKS
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FORMULA
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If n = Product_j (p_j)^(e_j) is the prime factorization of n, then a(n) = Product_j p_j^(n e_j - 1) * gcd(Product_j p_j, Product_j (p_j-1)). - Robert Israel, Jan 18 2018
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MAPLE
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f:= proc(n) local F, x;
F:= ifactors(n)[2];
mul(x[1]^(n*x[2]-1), x=F) * igcd(mul(x[1], x=F), mul(x[1]-1, x=F))
end proc:
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PROG
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(PARI) { for (n=1, 100, p=n^n; write("b064448.txt", n, " ", gcd(p, eulerphi(p))) ) } \\ Harry J. Smith, Sep 14 2009
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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