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A051233 Number of unit squares at least 50% covered by a circle inscribed in an integer square of size n X n. 2

%I

%S 1,4,9,12,21,32,37,52,65,80,97,112,137,152,177,208,225,256,289,316,

%T 349,384,421,448,489,536,577,612,665,716,749,812,857,912,965,1020,

%U 1085,1124,1201,1264,1313

%N Number of unit squares at least 50% covered by a circle inscribed in an integer square of size n X n.

%C From _Robert G. Wilson v_, Mar 20 2017: (Start)

%C For n odd, the center of the circle is in the middle of the center square and thus a(2n-1) == 1 (mod 4).

%C For n even, the center of the circle is at the four corners of the center 4 squares and thus a(2n) == 0 (mod 4). (End)

%e a(2)=4 because an inscribed circle in a 2 X 2 grid covers 50% of all the unit squares within it.

%K nonn,more

%O 1,2

%A Joe K. Crump (joecr(AT)carolina.rr.com)

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Last modified July 24 05:07 EDT 2019. Contains 325290 sequences. (Running on oeis4.)