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Sum of digits of n < number of divisors of n.
3

%I #13 Apr 05 2015 08:55:50

%S 10,12,20,21,24,30,32,40,42,50,60,70,72,80,90,100,102,104,105,108,110,

%T 111,112,114,120,126,130,132,140,144,150,160,162,168,180,192,200,201,

%U 204,210,212,216,220,222,224,230,231,232,234,240,250,252,260,264,270

%N Sum of digits of n < number of divisors of n.

%F Solutions to A007953[x] < A000005[x]

%e All are special composites.

%t sud[x_] := Apply[Plus, IntegerDigits[x]] Do[s=sud[n]-DivisorSigma[0, n]; If[s>0, Print[n]], {n, 1, 256}]

%t Select[Range[300],Total[IntegerDigits[#]]<DivisorSigma[0,#]&] (* _Harvey P. Dale_, Apr 05 2015 *)

%Y Cf. A007953, A000005, A057531, A075492, A075493.

%K base,easy,nonn

%O 1,1

%A _Labos Elemer_, Sep 26 2002