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%I #28 Aug 25 2014 14:44:30
%S 10,22,34,47,60,72,84,98,110,122,135,148,160,172,186,198,210,223,236,
%T 248,260,274,286,298,311,324,336,348,362,374,386,399,412,424,436,450,
%U 462,474,487,500,512,524,538,550,562,575,588,600,612,626,638,650,663
%N Number of integers between -(2*n+1)*Pi and (2*n+2)*Pi.
%C a(n) is the number of lattice points inside spiral r=theta and on X-axis counted until the (n+1)-th loop of the spiral.
%H César Eliud Lozada, <a href="/A217573/a217573.gif">Plot of spiral</a>
%F a(n) = floor((2*n+1)*Pi) + floor((2*n+2)*Pi) + 1.
%p A := []:
%p for n from 0 to 80 do
%p n1 := floor((2*n+1)*Pi):
%p n2 := floor((2*n+2)*Pi):
%p A := [op(A), n1+n2+1]
%p end do:
%p A:=A;
%t Table[Ceiling[Pi(2n+2)]+Floor[Pi(2n+1)],{n,0,60}] (* _Harvey P. Dale_, Aug 25 2014 *)
%Y Cf. A001951.
%K nonn
%O 0,1
%A _César Eliud Lozada_, Oct 08 2012
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