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A068698
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Smallest primes in the reverse concatenation of n consecutive odd numbers.
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0
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3, 31, 0, 59575553, 15131197, 0, 55535149474543, 6361595755535149, 0, 1151131111091071051031019997, 207205203201199197195193191189187, 0, 65636159575553514947454341, 4543413937353331292725232119, 0
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OFFSET
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1,1
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LINKS
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EXAMPLE
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a(5) = 15131197 is a prime and a concatenation of 15,13,11,9 and 7.
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MAPLE
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for n from 1 to 32 do d := 0:c := true: if((n mod 3)=0) then c := false:a := 0:end if: while(c=true) do a := 2*(n+d)-1:for j from 1 to n-1 do a := 2*(n+d-j)-1+10^( floor(evalf(log(2*(n+d-j)-1)/log(10))+0.0000000001 )+1)*a:end do: if(isprime(a))then c := false:end if:d := d+1:end do:b[n] := a:end do:seq(b[h], h=1..32);
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CROSSREFS
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KEYWORD
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base,hard,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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