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%I A185250 #26 Sep 03 2013 23:55:52
%S A185250 2,7,23,67,61,83,107,829,109,809,127,827,163,683,163,863,167,283,167,
%T A185250 823,181,881,211,887,223,677,227,277,227,727,239,607,241,587,241,857,
%U A185250 251,487,263,367,263,673,269,307,271,827,283,617,283,761,293,607,383,661
%N A185250 Array A(n,k), n > 0, k = 1,2 read by rows such that (A(n,1),  A(n,2)) are the pairs of primes (p, q), p < q, where the decimal digits of q are the 9's complement of the decimal digits of p.
%C A185250 The prime p in the pair (p, q) is not unique; for example, the prime 163 generates two pairs of primes: (163, 683) and (163, 863).
%H A185250 Michel Lagneau, <a href="/A185250/b185250.txt">Table of (p, q) for 5000 pairs</a>
%e A185250 (241, 587) and (241, 857) are in the sequence because the digits 5, 8, 7  are the 9's complement of the decimal digits of 241.
%p A185250 with(numtheory):
%p A185250      for n from 1 to 200 do:
%p A185250         p1:=ithprime(n)
%p A185250          for k from n+1 to 2000 do:
%p A185250           p2:=ithprime(k):
%p A185250           x1:=convert(p1,base,10):n1:=nops(x1):
%p A185250           x2:=convert(p2,base,10):n2:=nops(x2):
%p A185250             if n1=n2 then
%p A185250             W:=array(1..n1):U:=array(1..n1):U1:=array(1..n1):
%p A185250               for c from 1 to n1 do:
%p A185250               U1[c]:=x1[c]:od:U:=sort(x1,`<`):V:=sort(x2,`>`):
%p A185250                  for j from 1 to n1 do:
%p A185250                    W[j]:= 9-V[j]:od:W1:=sort(W,`>`):jj:=0:
%p A185250                      for b from 1 to n1 do:
%p A185250                      if U[b]=W1[b] then jj:=jj+1:
%p A185250                      else
%p A185250                      fi:
%p A185250                      od:
%p A185250                      if jj=n1 and p1<p2
%p A185250                      then
%p A185250                      printf(`%d, `,p1):
%p A185250                      printf(`%d, `,p2):else
%p A185250                      fi:
%p A185250               fi:
%p A185250            od:
%p A185250          od:
%Y A185250 Cf. A228629.
%K A185250 nonn,base,less
%O A185250 1,1
%A A185250 _Michel Lagneau_, Aug 29 2013

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