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%I #8 Jun 14 2014 21:11:30
%S 25,35,1147,1159,1189,1343,1711,1943,1961,2911,2923,3713,4171,4183,
%T 4189,4331,4717,5329,5917,101263,101461,101617,101659,101887,101911,
%U 101971,103127,103223,103277,103283,103331,103373,103463,103487,103601,103709,103739,103877
%N Semiprimes which are products of two primes each with half the number of digits, and which when split in the middle gives two primes; no leading zeros.
%H Andreas Boe, <a href="/A243749/b243749.txt">Table of n, a(n) for n = 1..10766</a>
%e 1961=37*53 has 4 digits and is the product of two 2-digit primes, and 1961 -> 19 and 61 also gives two 2-digit primes.
%o (PARI) isok(n) = (bigomega(n) == 2) && (len = #Str(n)) && !(len % 2) && (f=factor(n)) && prod(i=1, #f~, #Str(f[i,1])== len/2) && isprime(n\10^(len/2)) && isprime(q=n % 10^(len/2)) && (#Str(q)== len/2); \\ _Michel Marcus_, Jun 10 2014
%K nonn,base
%O 1,1
%A _Andreas Boe_, Jun 09 2014
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