%I #15 Jan 16 2021 01:25:32
%S 3,9,105,1365,884037
%N a(n) is the smallest product of n (not necessarily distinct) odd primes m = p_1*p_2*...*p_n such that (d+m/d)/2 is a prime for all d dividing m.
%C This sequence differs from A128281 only in the value A128281(2)=21: a(2)=9 since, for n=2 only, the specification "distinct primes" makes a difference.
%e a(2) = 9 = 3*3 since (1+9)/2=5 and (3+3)/2=3.
%Y Cf. A128281, A128283, A340482.
%K nonn,hard,more
%O 1,1
%A _Hartmut F. W. Hoft_, Jan 09 2021
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