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Search: id:A071339
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| A071339 |
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a(n) = the maximum number of lattice points touched by an origin-centered circle with radius <= n. |
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+0
9
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| 1, 4, 4, 8, 8, 12, 12, 12, 12, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 36, 36, 36
(list; graph; listen)
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OFFSET
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0,2
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LINKS
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Hugo Pfoertner, FORTRAN program for A071339-A071347
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FORMULA
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a(n) = max(i=0 to n^2) A004018(i)
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EXAMPLE
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a(5 to 8)=12 because the circle with radius 5 touches 12 lattice points: (+-1,+-2), (+-2,+-1), (+-5,0), (0,+-5); but no circle touches more, until the radius is sqrt(65).
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CROSSREFS
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Cf. A004018, A071339-A071347, A071383-A071385.
Adjacent sequences: A071336 A071337 A071338 this_sequence A071340 A071341 A071342
Sequence in context: A076359 A105675 A053249 this_sequence A101921 A093340 A046558
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KEYWORD
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easy,nonn
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AUTHOR
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Hugo Pfoertner (hugo(AT)pfoertner.org), May 22 2002
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EXTENSIONS
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Edited by Don Reble (djr(AT)nk.ca), Nov 06 2005
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