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%I #23 Feb 09 2021 02:49:22
%S 846,1682,2890,3626,5048,10926,14750,15850,17406,19942,22022,22023,
%T 22626,23274,24649,24650,25774,29350,30250,30925,30926,33174,36702,
%U 37250,38726,39446,40474,45374,47674,47675,47726,47826,48374,49490,54586,55026,55449,55450,57122,57123,58474,58850
%N Central element of a series of 5 successive nonsquarefree numbers.
%C Each of a(n), a(n)-1, a(n)-2, a(n)+1, a(n)+2 has at least one square divisor.
%H Amiram Eldar, <a href="/A188296/b188296.txt">Table of n, a(n) for n = 1..10000</a>
%F a(n) = A078144(n) + 2. - _Amiram Eldar_, Feb 09 2021
%e 846 = 2*3^2*47, 846 - 1 = 5*13^2, 846 - 2 = 2^2*211, 846 + 1 = 7*11^2, 846 + 2 = 2^4*53.
%t Select[Range[1,100000],!SquareFreeQ[#] &&!SquareFreeQ[#-1] &&!SquareFreeQ[#+1] &&!SquareFreeQ[#-2] &&!SquareFreeQ[#+2]&]
%Y Cf. A005117, A013929, A078144.
%K nonn
%O 1,1
%A _Vladimir Joseph Stephan Orlovsky_, Mar 29 2011
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