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A338009
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Odd composite integers m such that A004254(m)^2 == 1 (mod m).
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4
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25, 55, 115, 209, 253, 275, 319, 391, 425, 527, 551, 575, 713, 715, 775, 779, 935, 1105, 1111, 1265, 1705, 1807, 1919, 2015, 2035, 2071, 2575, 2627, 2893, 2915, 2929, 3281, 3289, 3655, 4031, 4033, 4141, 4199, 4355, 5191, 5291, 5671, 5699, 5777, 5885, 5983
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OFFSET
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1,1
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COMMENTS
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For a, b integers, the generalized Lucas sequence is defined by the relation U(n+2)=a*U(n+1)-b*U(n) and U(0)=0, U(1)=1.
This sequence satisfies the relation U(p)^2 == 1 for p prime and b=1,-1.
The composite numbers with this property may be called weak generalized Lucas pseudoprimes of parameters a and b.
The current sequence is defined for a=5 and b=1.
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REFERENCES
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D. Andrica and O. Bagdasar, Recurrent Sequences: Key Results, Applications and Problems. Springer (2020).
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LINKS
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MATHEMATICA
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Select[Range[3, 5985, 2], CompositeQ[#] && Divisible[ChebyshevU[#-1, 5/2]*ChebyshevU[#-1, 5/2] - 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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STATUS
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approved
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