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A052199
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Numbers that are expressible as the sum of 2 distinct positive squares in more ways than any smaller number.
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8
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1, 5, 65, 325, 1105, 5525, 27625, 71825, 138125, 160225, 801125, 2082925, 4005625, 5928325, 29641625, 77068225, 148208125, 243061325, 1215306625, 3159797225, 6076533125, 12882250225, 53716552825, 64411251125, 167469252925, 322056255625, 785817263725
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listen;
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OFFSET
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1,2
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REFERENCES
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Donald S. McDonald, Postings to sci.math newsgroup, Feb 21, 1995 and Dec 04, 1995.
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LINKS
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Dirk Frettlöh, "Tile Orientations with Distinct Frequencies", Ch. 1.5 in Aperiodic Order, Vol. 2: Crystallography and Almost Periodicity, 2017, see page 9.
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EXAMPLE
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65 = 1^2 + 8^2 = 4^2 + 7^2, the smallest expressible in two ways, so 65 is a term.
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PROG
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(PARI)
c_old=-1; for(n=1, 10000, c=0; for(i=1, floor(sqrt(n)), for(j=1, i-1, if(i^2+j^2==n, c+=1))); if(c>c_old, print1(n, ", "); c_old=c)) \\ Derek Orr, Mar 15 2019
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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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