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A232893 Numbers whose sum of square divisors is a palindrome in base 10 having at least two digits. 1

%I #9 Jan 31 2016 12:13:48

%S 15376,30752,46128,76880,92256,107632,153760,169136,199888,215264,

%T 230640,261392,292144,322896,338272,353648,399776,445904,461280,

%U 476656,507408,522784,538160,568912,584288,599664,630416,645792,661168,707296,722672,784176,814928,845680,876432

%N Numbers whose sum of square divisors is a palindrome in base 10 having at least two digits.

%e Sum of square divisor of 15376, 15376+3844+961+16+4+1=20202, a palindrome with five digits.

%t ssdpQ[n_]:=Module[{s=Total[Select[Divisors[n],IntegerQ[Sqrt[#]]&]]}, IntegerLength[ s]>1 &&s==IntegerReverse[s]]; Select[Range[ 900000], ssdpQ] (* The program uses the IntegerReverse function from Mathematica version 10 *) (* _Harvey P. Dale_, Jan 31 2016 *)

%o (PARI)

%o reverse(n)=concat(Vecrev(Str(n)))

%o palind(n)=(Str(n)==reverse(n)&&n>10)

%o {for(n=1,10^6,k=sumdiv(n,d,d*issquare(d));if(palind(k),print(n)))}

%Y Cf. A232892.

%K nonn,base

%O 1,1

%A _Antonio Roldán_, Dec 02 2013

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Last modified April 25 10:51 EDT 2024. Contains 371967 sequences. (Running on oeis4.)