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A124980
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Smallest strictly positive number decomposable in n different ways as a sum of two squares.
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5
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1, 25, 325, 1105, 4225, 5525, 203125, 27625, 71825, 138125, 2640625, 160225, 17850625, 1221025, 1795625, 801125, 1650390625, 2082925, 49591064453125, 4005625, 44890625, 2158203125, 30525625, 5928325, 303460625, 53955078125, 35409725, 100140625
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OFFSET
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1,2
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LINKS
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FORMULA
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EXAMPLE
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a(3)=325 is decomposable in 3 ways: 15^2 + 10^2 = 17^2 + 6^2 = 18^2 + 1^2.
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PROG
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(PARI) cnt2sqr(n)={local(cnt=0, y2) ; for(x=0, floor(sqrt(n)), y2=n-x^2 ; if( y2>=x^2 && issquare(y2), cnt++ ; ) ; ) ; return(cnt) ; } A124980(n)= { local(a=1) ; while(1, if( cnt2sqr(a)==n, return(a) ; ) ; a++ ; ) ; } { for(n=1, 100, print(n, " ", A124980(n)) ; ) ; } \\ R. J. Mathar, Nov 29 2006
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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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