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Largest square <= sigma(n).
1

%I #16 Jun 17 2018 03:42:36

%S 1,1,4,4,4,9,4,9,9,16,9,25,9,16,16,25,16,36,16,36,25,36,16,49,25,36,

%T 36,49,25,64,25,49,36,49,36,81,36,49,49,81,36,81,36,81,64,64,36,121,

%U 49,81,64,81,49,100,64,100,64,81,49,144,49,81,100,121,81,144,64,121,81,144

%N Largest square <= sigma(n).

%H Harry J. Smith, <a href="/A065734/b065734.txt">Table of n, a(n) for n = 1..1000</a>

%F a(n) = A048760(A000203(n)).

%t Table[Floor[Sqrt[DivisorSigma[1,n]]]^2,{n,70}] (* _Harvey P. Dale_, Oct 05 2015 *)

%o (PARI) { for (n=1, 1000, a=sqrtint(sigma(n))^2; write("b065734.txt", n, " ", a) ) } \\ _Harry J. Smith_, Oct 28 2009

%o (Maxima)

%o A000203(n) := divsum(n) ;

%o A048760(n) := (floor(sqrt(n)))^2 ;

%o A065734(n) := A048760(A000203(n)) ;

%o for n from 1 thru 10 do print(A065734(n)) ; /* _R. J. Mathar_, Feb 13 2012 */

%Y Cf. A048760, A000203, A065730-A065741.

%K easy,nonn

%O 1,3

%A _Labos Elemer_, Nov 15 2001

%E Previous Mathematica program replaced by _Harvey P. Dale_, Oct 05 2015