%I #10 Jul 22 2020 09:41:18
%S 2,7,12,19,24,31,36,41,48,53,60,65,70,77,82,89,94,101,106,111,118,123,
%T 130,135,140,147,152,159,164,171,176,181,188,193,200,205,210,217,222,
%U 229,234,239,246,251,258,263,270,275,280,287,292,299,304,309,316,321,328,333,340,345,350,357,362,369,374,379,386,391,398,403,408,415,420
%N Positions of 0 in A188038; complement of A188040.
%C See A188014.
%C There is (conjecturally) a connection a(1+n) = f(n) where f(n) = 3*n +2 +2*floor(n*sqrt 2) is defined in A120861. Tested numerically up to n=40000. - _R. J. Mathar_, Jul 22 2020
%H G. C. Greubel, <a href="/A188039/b188039.txt">Table of n, a(n) for n = 1..10000</a>
%p A188038 := proc(n)
%p if n = 1 then
%p 1;
%p else
%p floor(n*sqrt(2))-floor((n-2)*sqrt(2))-2 ;
%p end if;
%p end proc:
%p isA188039 := proc(n)
%p if A188038(n) = 0 then
%p true;
%p else
%p false;
%p end if;
%p end proc:
%p A188039 := proc(n)
%p option remember;
%p if n = 1 then
%p 2;
%p else
%p for a from procname(n-1)+1 do
%p if isA188039(a) then
%p return a;
%p end if;
%p end do:
%p end if;
%p end proc: # _R. J. Mathar_, Jul 22 2020
%t r=2^(1/2)); k=2;
%t t=Table[Floor[n*r]-Floor[(n-k)*r]-Floor[k*r],{n,1,220}] (*A188038*)
%t Flatten[Position[t,0]] (*A188039*)
%t Flatten[Position[t,1]] (*A188040*)
%Y Cf. A188038, A188014, A188040.
%K nonn
%O 1,1
%A _Clark Kimberling_, Mar 19 2011
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