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0, 1, 2, 4, 8, 12, 18, 22, 30, 38, 48, 56, 66, 78, 96, 110, 120, 136, 154, 168, 192, 208, 232, 250, 278, 298, 320, 346, 372, 396, 426, 454, 490, 518, 556, 586, 620, 650, 688, 728, 766, 796, 840, 870, 924, 964, 1004, 1044, 1098, 1144, 1194, 1244, 1296, 1340, 1392, 1440
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internal format)
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OFFSET
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0,3
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LINKS
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FORMULA
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MAPLE
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A175341 := proc(n) local a, x, y ; a := 0 ; for x from -n to n do for y from -n to n do if x^2+y^2 <= n^2 and gcd(x, y) = 1 then a := a+1 ; end if; end do: end do: a ; end proc: seq(A175341(n)/4, n=0..40) ; # R. J. Mathar, Apr 20 2010
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MATHEMATICA
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a89[n_] := a89[n] = Product[{p, e} = pe; Which[p < 3 && e == 1, 1, p == 2 && e > 1, 0, Mod[p, 4] == 1, 2, Mod[p, 4] == 3, 0, True, a89[p^e]], {pe, FactorInteger[n]}];
b[n_] := b[n] = If[n == 0, 0, b[n-1] + 4 a89[n]];
a[n_] := b[n^2]/4;
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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