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A036705 Number of Gaussian integers z=a+bi satisfying n - 1/2 < |z| <= n + 1/2. 2
1, 8, 12, 16, 32, 28, 40, 40, 48, 68, 56, 72, 68, 88, 88, 84, 112, 112, 112, 116, 112, 144, 140, 144, 144, 168, 164, 160, 184, 172, 200, 192, 188, 208, 224, 224, 228, 224, 248, 236, 264, 248, 264, 276, 264, 288, 276, 304, 304, 312 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

Number of integer Cartesian grid points covered by a ring around the origin with width 1 and outer radius n + 1/2. - Ralf Stephan, Nov 28 2013

LINKS

Table of n, a(n) for n=0..49.

Index entries for Gaussian integers and primes

PROG

(PARI) a(n)=sum(i=-n, n, sum(j=-n, n, d=sqrt(i*i+j*j); if(d>=n-1/2&&d<=n+1/2, 1))) \\ Ralf Stephan, Nov 28 2013

CROSSREFS

Cf. A047077, A232705.

Sequence in context: A273800 A273798 A163283 * A129150 A175975 A030752

Adjacent sequences:  A036702 A036703 A036704 * A036706 A036707 A036708

KEYWORD

nonn

AUTHOR

Clark Kimberling

EXTENSIONS

Edited by Ralf Stephan, Nov 28 2013

STATUS

approved

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Last modified March 26 23:02 EDT 2019. Contains 321565 sequences. (Running on oeis4.)