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

1, 21, 41, 120, 242, 312, 323, 401, 501, 1040, 1114, 1141, 1204, 1214, 1233, 1241, 1304, 1503, 2033, 2115, 2133, 2140, 2403, 3010, 3014, 3124, 3211, 3304, 3322, 4001, 4012, 4121, 4301, 4310, 5130, 10044, 10214, 10242, 10320, 10324, 11042, 11115

Offset: 1

Author

Labos Elemer, Jan 16 2002

Keywords

• base
• nonn

Examples

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

Links

• Harvey P. Dale, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A067342, A067343, A007953, A001157.

Programs

Mathematica

Do[s=Apply[Plus, IntegerDigits[DivisorSigma[2, n]]]- Apply[Plus, IntegerDigits[n]^2]; If[Equal[s, 0], Print[n]], {n, 1, 10000}]
Select[Range[12000],Total[Flatten[IntegerDigits[#]^2]]== Total[ IntegerDigits[ DivisorSigma[2,#]]]&] (* Harvey P. Dale, Sep 12 2012 *)

Formula

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