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A057961
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Number of points in square lattice covered by a disc centered at (0,0) as its radius increases.
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8
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1, 5, 9, 13, 21, 25, 29, 37, 45, 49, 57, 61, 69, 81, 89, 97, 101, 109, 113, 121, 129, 137, 145, 149, 161, 169, 177, 185, 193, 197, 213, 221, 225, 233, 241, 249, 253, 261, 277, 285, 293, 301, 305, 317, 325, 333, 341, 349, 357, 365, 373, 377, 385, 401, 405, 421
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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COMMENTS
| Useful for rasterizing circles.
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REFERENCES
| J. H. Conway and N. J. A. Sloane, "Sphere Packings, Lattices and Groups", Springer-Verlag, p. 106.
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LINKS
| T. D. Noe, Table of n, a(n) for n=1..1000
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EXAMPLE
| a(2)=5 because (0,0); (0,1); (0,-1); (1,0); (-1,0) are covered by any disc of radius between 1 and sqrt(2).
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CROSSREFS
| Cf. A004018, A004020, A005883, A057962. Distinct terms of A057655.
Sequence in context: A046586 A023493 A087461 * A089217 A166049 A053411
Adjacent sequences: A057958 A057959 A057960 * A057962 A057963 A057964
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KEYWORD
| easy,nonn
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AUTHOR
| Ken Takusagawa (kenta(AT)cs.stanford.edu), Oct 15 2000
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