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A211339
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Number of integer pairs (x,y) such that 1<x<=y<=n and x^2+y^2<=n.
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1
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0, 1, 1, 1, 2, 2, 2, 3, 3, 4, 4, 4, 5, 5, 5, 5, 6, 7, 7, 8, 8, 8, 8, 8, 9, 10, 10, 10, 11, 11, 11, 12, 12, 13, 13, 13, 14, 14, 14, 15, 16, 16, 16, 16, 17, 17, 17, 17, 17, 19, 19, 20, 21, 21, 21, 21, 21, 22, 22, 22, 23, 23, 23, 23, 25, 25, 25, 26, 26, 26, 26, 27, 28, 29
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OFFSET
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1,5
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COMMENTS
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Partial sums of A025426.
For a guide to related sequences, see A211266.
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LINKS
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Table of n, a(n) for n=1..74.
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MATHEMATICA
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a = 1; b = n; z1 = 120;
t[n_] := t[n] = Flatten[Table[x^2 + y^2, {x, a, b - 1}, {y, x, b}]]
c[n_, k_] := c[n, k] = Count[t[n], k]
TableForm[Table[c[n, k], {n, 1, 10}, {k, 1, 2 n}]]
Table[c[n, n], {n, 1, z1}] (* A025426 *)
c1[n_, m_] := c1[n, m] = Sum[c[n, k], {k, a, m}]
Table[c1[n, n], {n, 1, z1}] (* A211339 *)
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CROSSREFS
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Cf. A211266.
Sequence in context: A152595 A176844 A085182 * A087739 A127763 A057367
Adjacent sequences: A211336 A211337 A211338 * A211340 A211341 A211342
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KEYWORD
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nonn
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AUTHOR
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Clark Kimberling, Apr 08 2012
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STATUS
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approved
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