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A231472
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Largest integer less than 12 and coprime to n.
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1
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11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 10, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 9, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 10, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 9, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 9, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 7, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 10
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OFFSET
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1,1
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COMMENTS
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Values in this sequence are 1, 5, 7, 8, 9, 10, and 11; the average value is 3569/330 = 10.81515.... - Charles R Greathouse IV, Aug 19 2016
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LINKS
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EXAMPLE
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a(1..10)=11 because this is the largest integer less than 12 and it is coprime to n=1,...,10.
a(11)=10 because 11 is not coprime to 11 but 10 is.
a(22)=9 because 11 and 10 are not coprime to 22=2*11.
a(2310)=1 because 2310=2*3*5*7*11 is not coprime to any number n>1, n<12.
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MATHEMATICA
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Table[SelectFirst[Range[11, 1, -1], CoprimeQ[#, n]&], {n, 80}] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Mar 02 2018 *)
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PROG
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(PARI) a(n, m=12)=for(k=1, m, gcd(n, m-k)==1&&return(m-k))
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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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