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%I #2 Mar 30 2012 17:26:34
%S 1,9,13,25,133,193,18673,57313,1032313,4387273
%N a(1) = 1; for n>1, a(n) = smallest number of the form 4k+1 and a(n) > a(n-1) such that the pairwise sums of elements are all semiprimes.
%C Or, for i<>j, (a(i)+a(j)/2 are primes.
%C Starting with a(5)=133 on all terms === 13 mod 20.
%C Is sequence finite?
%Y Cf. A175533.
%K nonn
%O 1,2
%A _Zak Seidov_, Jun 12 2010
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