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A188525
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a(n) = rad(rad(n)^2+1), where rad = A007947.
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1
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2, 5, 10, 5, 26, 37, 10, 5, 10, 101, 122, 37, 170, 197, 226, 5, 290, 37, 362, 101, 442, 485, 530, 37, 26, 677, 10, 197, 842, 901, 962, 5, 1090, 1157, 1226, 37, 1370, 85, 1522, 101, 58, 1765, 370, 485, 226, 2117, 2210, 37, 10, 101, 2602, 677, 2810, 37
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OFFSET
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1,1
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LINKS
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FORMULA
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EXAMPLE
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a(7) = rad(rad(7)^2 + 1) = rad(7^2 + 1) = rad(50) = 10.
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MAPLE
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with(numtheory):
rad:= n-> mul(i, i=factorset(n)):
a:= n-> rad(rad(n)^2+1):
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MATHEMATICA
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rad[n_] := Times @@ FactorInteger[n][[All, 1]];
a[n_] := rad[rad[n]^2 + 1];
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PROG
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(Magma) [ &*PrimeDivisors((&*PrimeDivisors(n))^2+1): n in [1..51] ]; // Bruno Berselli, Apr 04 2011
(PARI) rad(n)=my(f=factor(n)[, 1]); prod(i=1, #f, f[i])
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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