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A075492
Sum of digits of n < number of divisors of n.
3
10, 12, 20, 21, 24, 30, 32, 40, 42, 50, 60, 70, 72, 80, 90, 100, 102, 104, 105, 108, 110, 111, 112, 114, 120, 126, 130, 132, 140, 144, 150, 160, 162, 168, 180, 192, 200, 201, 204, 210, 212, 216, 220, 222, 224, 230, 231, 232, 234, 240, 250, 252, 260, 264, 270
OFFSET
1,1
FORMULA
Solutions to A007953[x] < A000005[x]
EXAMPLE
All are special composites.
MATHEMATICA
sud[x_] := Apply[Plus, IntegerDigits[x]] Do[s=sud[n]-DivisorSigma[0, n]; If[s>0, Print[n]], {n, 1, 256}]
Select[Range[300], Total[IntegerDigits[#]]<DivisorSigma[0, #]&] (* Harvey P. Dale, Apr 05 2015 *)
CROSSREFS
KEYWORD
base,easy,nonn
AUTHOR
Labos Elemer, Sep 26 2002
STATUS
approved