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A306103
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Numbers that are the difference of two positive squares in at least three ways.
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3
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45, 48, 63, 72, 75, 80, 96, 99, 105, 112, 117, 120, 128, 135, 144, 147, 153, 160, 165, 168, 171, 175, 176, 180, 189, 192, 195, 200, 207, 208, 216, 224, 225, 231, 240, 243, 245, 252, 255, 256, 261, 264, 272, 273, 275, 279, 280, 285, 288, 297, 300
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OFFSET
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1,1
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COMMENTS
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Numbers n such that A100073(n) >= 3; see there for more information & formulas.
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LINKS
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FORMULA
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EXAMPLE
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48 = 7^2 - 1^2 = 8^2 - 4^2 = 13^2 - 11^2.
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MATHEMATICA
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Select[Range[300], Length[FindInstance[x^2 - y^2 == # && x>y>0, {x, y}, Integers, 3 ]] == 3 &] (* Giovanni Resta, Jul 10 2018 *)
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PROG
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(PARI) select( is(n)=A100073(n)>2, [1..300])
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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