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First of three consecutive numbers with at least one 3 in their prime signature.
5

%I #14 Sep 09 2019 18:01:26

%S 6858,22625,28375,40472,48248,49624,58374,59750,94471,102248,103624,

%T 107702,112374,122823,129623,133623,136214,136375,153063,164295,

%U 187623,190375,197910,199624,210248,211624,220374,221750,238248,246616,260874,264248,275750,280231,298375,300806,312471,329623,336824,346086,349623,352375,356375

%N First of three consecutive numbers with at least one 3 in their prime signature.

%H Harvey P. Dale, <a href="/A176350/b176350.txt">Table of n, a(n) for n = 1..1000</a>

%e 6858=2*3^3*127,6859=19^3,6860=2^2*5*7^3,..

%t f[n_]:=MemberQ[Last/@FactorInteger[n], 3]; Select[Range[9!],f[#]&&f[#+1]&&f[#+2]&]

%t SequencePosition[Table[If[MemberQ[FactorInteger[n][[All,2]],3],1,0],{n,360000}],{1,1,1}][[All,1]] (* Requires Mathematica version 10 or later *) (* _Harvey P. Dale_, Sep 09 2019 *)

%Y Cf. A000578, A001235, A176297, A176313.

%K nonn

%O 1,1

%A _Vladimir Joseph Stephan Orlovsky_, Dec 07 2010

%E Edited by _Matthew Vandermast_, Dec 09 2010