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A088041
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Smallest k such that k^4 - 1 is divisible by an n-th power, k > 1.
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3
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2, 3, 3, 3, 7, 15, 31, 63, 127, 255, 511, 1023, 2047, 4095, 8191, 16383, 32767, 65535, 131071, 262143, 524287, 1048575, 2097151, 4194303, 8388607, 16777215, 33554431, 67108863, 134217727, 268435455, 536870911, 1073741823, 2147483647
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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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Apparently a(n) = 2^(n-2) - 1 for n>3.
Conjecture: a(n) = 3*a(n-1)-2*a(n-2) for n>5. G.f.: x*(4*x^4-2*x^2-3*x+2) / ((x-1)*(2*x-1)). [Colin Barker, Feb 05 2013]
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MAPLE
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MATHEMATICA
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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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