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

1,2

Links

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

Formula

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

Example

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

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 *)

Crossrefs

Cf. A067342, A067343, A007953, A001157.

Sequence in context: A173960 A147273 A195034 * A053428 A123842 A247387

Adjacent sequences: A067341 A067342 A067343 * A067345 A067346 A067347

Keyword

base,nonn

Author

Labos Elemer, Jan 16 2002

Status

approved