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A300167
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Numbers n such that n^2+1 can be expressed as j^2+k^2, j>k>1, gcd(j,k)=1, in more ways than for any smaller n.
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4
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OFFSET
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1,1
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LINKS
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Table of n, a(n) for n=1..10.
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EXAMPLE
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a(1)= 8 because 8^2 + 1 = A300168(1) = 65 = 7^2 + 4^2.
a(2) = 47 because it is the smallest n leading to more than 1 way of expressing n^2+1 : 47^2 + 1 = 2010 = 43^2 + 19^2 = 41^2 + 23^2 = 37^2 + 29^2.
a(3) = 242 because 242^2 + 1 = 58565 is the smallest number that can be expressed in more than 3 ways:
58565 = 241^2 + 22^2 = 239^2 + 38^2 = 223^2 + 94^2 = 214^2 + 113^2 = 209^2 + 122^2 = 206^2 + 127^2 = 193^2 + 146^2.
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CROSSREFS
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Cf. A300161, A300165, A300168.
Sequence in context: A081279 A099110 A106393 * A029760 A139262 A026900
Adjacent sequences: A300164 A300165 A300166 * A300168 A300169 A300170
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KEYWORD
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nonn,hard,more
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AUTHOR
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Hugo Pfoertner, Feb 27 2018
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EXTENSIONS
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a(7) from Robert Price, Mar 11 2018
a(7) corrected, a(8)-a(9) added by Ray Chandler, Dec 23 2019
a(10) added by Ray Chandler, Dec 31 2019
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STATUS
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approved
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