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A182811
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Cyclops-Lucas numbers.
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2
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OFFSET
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1,1
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COMMENTS
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a(4) = 688846502588399 is the only known Cyclops-Lucas prime.
It seems likely that these four are the only terms. There are no further terms below Lucas(10^7), and that number in decimal contains 208435 zeros (with ~208988 expected assuming normality), whereas a member of this sequence must have only 1. - D. S. McNeil, Dec 21 2010
This sequence is similar to A182809 in the sense that both have four positive terms and the only known prime is also the largest known term. - Omar E. Pol, Dec 21 2010
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LINKS
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FORMULA
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EXAMPLE
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a(1) = 64079 is in the sequence because 64079 is a Lucas number and it is also a cyclops number.
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MATHEMATICA
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(* First run the program given for A134808 *) Select[LucasL[Range[10^3]], cyclopsQ] (* Alonso del Arte, Dec 20 2010 *)
Select[LucasL[Range[500]], OddQ[IntegerLength[#]]&&DigitCount[#, 10, 0]==1&&IntegerDigits[#][[(IntegerLength[#]+1)/2]]==0&] (* Harvey P. Dale, Jul 01 2017 *)
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CROSSREFS
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KEYWORD
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nonn,base,hard,more
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AUTHOR
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STATUS
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approved
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