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A036713
a(n)=number of Gaussian integers z=a+bi satisfying |z|<=n+1/2, a>=0, 0<=b<a.
1
0, 1, 3, 5, 9, 13, 18, 23, 29, 38, 45, 54, 63, 74, 85, 96, 110, 124, 138, 153, 167, 185, 203, 221, 239, 260, 281, 301, 324, 346, 371, 395, 419, 445, 473, 501, 530, 558, 589, 619, 652, 683, 716, 751, 784, 820, 855, 893, 931, 970, 1010
OFFSET
0,3
MAPLE
N:= 100: V:= Vector(N):
for a from 1 to N do
for b from 0 to a-1 do
nmin:= ceil(sqrt(a^2+b^2)-1/2);
if nmin > N then break fi;
V[nmin..N]:= V[nmin..N]+~1
od od:
0, seq(V[i], i=1..N); # Robert Israel, Jul 14 2019
CROSSREFS
Sequence in context: A075314 A152737 A032635 * A260733 A265429 A356254
KEYWORD
nonn
STATUS
approved