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A068785
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Number of Cartesian lattice points in or on the circle of radius 10^n.
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4
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OFFSET
| 0,2
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COMMENTS
| a(n) ~ pi*n. page 164. "Gauss gave a(100) = 317 and a(10,000) = 31417." page 165. a(10^8) = 314159053, a(10^10) = 31415925457, a(10^12) = 3141592649625 & a(10^14) = 314159265350589. page 234.
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REFERENCES
| Daniel Shanks, "Solved and Unsolved Problems in Number Theory," Fourth Edition, Chelsea Publishing Co., NY, 1993, pages 165 and 234.
Wolfram Research, Mathematica 4, Standard Add-On Packages, Wolfram Media, Inc., Champaign, Il, 1999, pages 322-3.
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LINKS
| Index entries for sequences related to populations of quadratic forms
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MATHEMATICA
| k = 1; s = 1; Do[s = s + SquaresR[2, n]; If[n == 10^k, k++; Print[s]], {n, 1, 10^6} ]
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CROSSREFS
| Cf. A004018, A057961, A057655.
Sequence in context: A114785 A061014 A130450 * A133554 A177513 A137834
Adjacent sequences: A068782 A068783 A068784 * A068786 A068787 A068788
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KEYWORD
| nonn
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AUTHOR
| Robert G. Wilson v (rgwv(AT)rgwv.com), Mar 07 2002
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