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A069112
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Squarefree part of 2^n-1 : the smallest number such that a(n)*(2^n-1) is a square.
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1
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1, 3, 7, 15, 31, 7, 127, 255, 511, 1023, 2047, 455, 8191, 16383, 32767, 65535, 131071, 29127, 524287, 41943, 42799, 4194303, 8388607, 1864135, 33554431, 67108863, 134217727, 268435455, 536870911, 119304647, 2147483647, 4294967295, 8589934591, 17179869183, 34359738367
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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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MATHEMATICA
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SquareFreePart[n_] := Times @@ Apply[Power, {First[#], Mod[Last[#], 2]}& /@ FactorInteger[n], {1}]; a[n_] := SquareFreePart[2^n-1]; Table[a[n], {n, 1, 32}] (* Jean-François Alcover, Apr 10 2014 *)
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PROG
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(PARI) for(n=1, 60, print1(core(2^n-1), ", "))
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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