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Numbers having at least two representations as sum of a squarefree number and a nonzero square.
2

%I #11 Feb 14 2015 13:53:34

%S 6,7,10,11,12,14,15,16,17,18,19,20,21,22,23,24,26,27,28,30,31,32,33,

%T 34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,

%U 57,58,59,60,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78

%N Numbers having at least two representations as sum of a squarefree number and a nonzero square.

%C Numbers n such that A085263(a(n)) > 1.

%C Conjecture: for n > 50, a(n) = n + 11. - _Charles R Greathouse IV_, Oct 26 2011

%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/SquareNumber.html">Square Number</a>

%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/Squarefree.html">Squarefree</a>

%o (PARI) is(n)=my(t);forstep(k=sqrtint(n-1),1,-1,if(issquarefree(n-k^2),if(t++>1,return(1))));0 \\ _Charles R Greathouse IV_, Mar 12 2012

%Y Cf. A085265, A085266.

%K nonn

%O 1,1

%A _Reinhard Zumkeller_, Jun 23 2003