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A168529
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Primes n that are concatenation of two 3-digit primes p<q.
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2
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101107, 101113, 101149, 101173, 101197, 101281, 101293, 101347, 101359, 101383, 101419, 101449, 101467, 101503, 101599, 101641, 101653, 101701, 101719, 101797, 101839, 101863, 101929, 101977, 103307, 103349, 103409, 103421, 103457, 103577
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OFFSET
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1,1
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COMMENTS
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Or, primes of the form 10^3*p+q, p,q primes, 100<p<q<998.
There are exactly 1407 such primes from 101107 to 971977.
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LINKS
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MATHEMATICA
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p3=Select[Range[100, 999], PrimeQ]; Le=Length@p3; Reap[Do[p=10^3*p3[[i]]; Do[If[PrimeQ[n=p+p3[[k]]], Sow[n]], {k, i+1, Le}], {i, Le-1}]][[2, 1]];
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PROG
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(PARI) concat(apply(p->select(n->isprime(n) && isprime(n%1000), [1000*p+p+1..1000*p+997]), select(isprime, [101..996]))) \\ Andrew Howroyd, Feb 22 2018
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CROSSREFS
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KEYWORD
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base,fini,full,nonn
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AUTHOR
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EXTENSIONS
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Terms a(25) and beyond in b-file corrected by Andrew Howroyd, Feb 22 2018
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STATUS
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approved
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