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A134428
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Primes formed by concatenating k with k+1, where k+1 is a prime.
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1
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23, 67, 1213, 3637, 4243, 7879, 9697, 102103, 108109, 126127, 138139, 150151, 156157, 180181, 192193, 270271, 276277, 312313, 330331, 378379, 420421, 432433, 438439, 456457, 522523, 540541, 546547, 576577, 600601, 606607, 612613, 618619
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OFFSET
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1,1
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COMMENTS
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LINKS
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MAPLE
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P:=proc(n) local a;
a:=(ithprime(n)-1)*10^(ilog10(ithprime(n))+1)+ithprime(n);
if isprime(a) then a; fi; end: seq(P(i), i=1..10^3);
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MATHEMATICA
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Select[Table[(p-1)*10^IntegerLength[p]+p, {p, Prime[Range[200]]}], PrimeQ] (* Harvey P. Dale, Aug 23 2019 *)
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CROSSREFS
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KEYWORD
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nonn,base,easy
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AUTHOR
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STATUS
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approved
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