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%I #11 Sep 30 2021 17:24:09
%S 423,603,1250,1375,2007,2523,2527,3175,4075,4203,4374,4923,4948,7442,
%T 8991,10375,10467,12591,18027,20402,20575,22023,22687,23823,26071,
%U 28375,30231,31507,31850,33271,34623,35574,36162,37348,40023,49975,50274,54475,54511,55323
%N Starts of runs of 3 consecutive numbers that have an equal number of unitary and nonunitary prime divisors (A348097).
%H Amiram Eldar, <a href="/A348099/b348099.txt">Table of n, a(n) for n = 1..10000</a>
%F 423 is a term since 423 = 3^2 * 47, 423 + 1 = 424 = 2^3 * 53 and 423 + 2 = 425 = 5^2 * 17 all have one unitary prime divisor and one nonunitary prime divisor.
%t q[n_] := n == 1 || Count[(e = FactorInteger[n][[;; , 2]]), 1] == Length[e]/2; v = q /@ Range[3]; seq = {}; Do[v = Append[Drop[v, 1], q[k]]; If[And @@ v, AppendTo[seq, k - 2]], {k, 4, 10^5}]; seq
%Y Subsequence of A348097 and A348098.
%Y Cf. A335397.
%K nonn
%O 1,1
%A _Amiram Eldar_, Sep 30 2021
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