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A075880 Position of the circles around (0,0) that contain record numbers of lattice points in the list of all circles around (0,0) that pass through lattice points, ordered by increasing radius. 3
0, 1, 4, 13, 30, 121, 362, 1232, 1584, 7121, 17548, 32649, 37603, 174926, 437750, 821432, 1198677, 5678338, 14335447, 27044791, 43735981, 209473053, 531787054, 1006745669, 2097411347, 8474384496, 10122355701 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,3
COMMENTS
The first terms of this sequence were given by James Buddenhagen in a sci.math posting on May 05 2002 entitled "Circle with 3 lattice points"
LINKS
James Buddenhagen, Circle with 3 lattice points, thread in NG sci.math.
FORMULA
a(n) = k-1 for which A001481(k) = A071383(n). lim n ->infinity a(n) = k_LR * exp(n) / n^(1/2), where k_LR is the Landau-Ramanujan constant 0.764223653... (A064533)
EXAMPLE
a(4)=13 because A001481(14) = A071383(4)=25.
CROSSREFS
Sequence in context: A022913 A232228 A218213 * A042487 A154753 A335981
KEYWORD
nonn
AUTHOR
Hugo Pfoertner, Oct 16 2002
EXTENSIONS
Minor edits to adjust formula and example for changes to offset of related sequences by Ray Chandler, Jan 13 2012
STATUS
approved

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Last modified March 29 10:44 EDT 2024. Contains 371268 sequences. (Running on oeis4.)