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%I #13 Jun 18 2018 05:38:01
%S 4,5,10,29,173,249,19073,71489,1166789,3800333,7021253,15920129,
%T 84551600693
%N The least increasing sequence of numbers where all pairwise sums are semiprimes, with a(1)=4.
%C All terms > 10 are congruent to {3, 9} mod 10.
%C Triangle of resulting semiprimes begins:
%C 9
%C 14, 15
%C 33, 34, 39
%C 177, 178, 183, 202
%t Nest[Append[#, Block[{k = Last[#] + 1}, While[! AllTrue[#, PrimeOmega[k + #] == 2 &], k++]; k]] &, {4}, 7] (* _Michael De Vlieger_, Jun 14 2018 *)
%Y Cf. A001358, A116656, A164979, A181620.
%K nonn,more
%O 1,1
%A _Zak Seidov_, Jun 14 2018
%E a(13) from _Giovanni Resta_, Jun 14 2018
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