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A244210 First differences of A244209.

%I A244210 #21 Feb 27 2018 16:30:02
%S A244210 8,-4,8,0,4,0,16,-12,8,0,12,-8,8,4,4,4,16,-16,4,0,16,-12,8,8,12,-8,8,
%T A244210 -4,0,0,28,-20,20,-8,8,4,0,0,-4,0,32,-4,0,-8,12,-8,8,4,20,-20,16,0,-4,
%U A244210 0,24,-20,8,8,20,-24,16,12,-16,8,12,-4,20,-8,8,-28,32,0,-4,-8,32
%N A244210 First differences of A244209.
%C A244210 All terms are even with some numbers missing, e.g., 2, 6, 10, 14, 18, 22, 26, 30, ... ,. For the first 1000 terms, the maximum is 136 at a(881) and the minimum is -156 at a(814).
%H A244210 Kival Ngaokrajang, <a href="/A244210/b244210.txt">Table of n, a(n) for n = 1..1000</a>
%o A244210 (Small Basic)
%o A244210 For n=1 to 200
%o A244210   count=0
%o A244210   row=math.Ceiling((n+1)/2)-1
%o A244210     for i=0 To row
%o A244210       for j=0 To row
%o A244210         x=math.power(4*i*i+4*j*j,1/2)
%o A244210         c1=-x+1-n
%o A244210         c2=-x-1+n
%o A244210         c3=-x+1+n
%o A244210         c4=x+1+n
%o A244210         If x>0 and c1*c2*c3*c4>0 then
%o A244210           c=(1/x)*math.Power(c1*c2*c3*c4,1/2)
%o A244210         Else
%o A244210           c=0
%o A244210         EndIf
%o A244210         If c>0 Then
%o A244210           count=count+1
%o A244210         EndIf
%o A244210       EndFor
%o A244210     EndFor
%o A244210   If Math.Remainder(n,2)=0 Then
%o A244210     circle[n]=4*(count-2)+4
%o A244210   Else
%o A244210     circle[n]=4*count
%o A244210   EndIf
%o A244210   If n > 1 Then
%o A244210     TextWindow.Write(circle[n]-circle[n-1]+", ")
%o A244210   EndIf
%o A244210 EndFor
%Y A244210 Cf. A244209.
%K A244210 sign
%O A244210 1,1
%A A244210 _Kival Ngaokrajang_, Jun 22 2014