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A067344 Sum of decimal digits of square of divisors of n equals sum of square of digits of n. 1

%I

%S 1,21,41,120,242,312,323,401,501,1040,1114,1141,1204,1214,1233,1241,

%T 1304,1503,2033,2115,2133,2140,2403,3010,3014,3124,3211,3304,3322,

%U 4001,4012,4121,4301,4310,5130,10044,10214,10242,10320,10324,11042,11115

%N Sum of decimal digits of square of divisors of n equals sum of square of digits of n.

%H Harvey P. Dale, <a href="/A067344/b067344.txt">Table of n, a(n) for n = 1..1000</a>

%F A007953[A001157(n)]=A007953[n]^2

%e n=51223, SquareSumDigit=25+1+4+4+9=43, Sigma[2,51223]=2623908580 with digit sum=43.

%t Do[s=Apply[Plus, IntegerDigits[DivisorSigma[2, n]]]- Apply[Plus, IntegerDigits[n]^2]; If[Equal[s, 0], Print[n]], {n, 1, 10000}]

%t Select[Range[12000],Total[Flatten[IntegerDigits[#]^2]]== Total[ IntegerDigits[ DivisorSigma[2,#]]]&] (* _Harvey P. Dale_, Sep 12 2012 *)

%Y Cf. A067342, A067343, A007953, A001157.

%K base,nonn

%O 1,2

%A _Labos Elemer_, Jan 16 2002

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Last modified January 25 07:33 EST 2020. Contains 331241 sequences. (Running on oeis4.)