A062179 - OEIS

%I #8 May 10 2013 12:44:47

%S 1,2,3,4,5,6,7,8,9,11,22,26,33,36,44,55,62,63,66,77,88,99,111,136,144,

%T 163,222,236,244,263,288,316,326,333,346,361,362,364,414,424,436,441,

%U 442,444,463,488,555,613,623,631,632,634,643,666,777,828,848,882,884

%N Harmonic mean of digits is an integer.

%H Harvey P. Dale, <a href="/A062179/b062179.txt">Table of n, a(n) for n = 1..1000</a>

%e 1236 is a term as the harmonic mean is 4/(1+1/2+1/3+1/6) = 2.

%t Do[ h = IntegerDigits[n]; If[ Sort[h] [[1]] != 0 && IntegerQ[ Length[h] / Apply[ Plus, 1/h] ], Print[n]], {n, 1, 10^4} ] Note that the number of entries <= 10^n are 9, 22, 61, 198, 927, 4738, 24620, 130093,

%t hmdiQ[n_]:=DigitCount[n,10,0]==0&&IntegerQ[HarmonicMean[ IntegerDigits[ n]]]; Select[Range[1000],hmdiQ] (* _Harvey P. Dale_, Sep 22 2012 *)

%Y Cf. A062180-A062185, A061383-A061388, A061423-A061425.

%K base,easy,nonn

%O 1,2

%A _Vladeta Jovovic_, Jun 12 2001

%E More terms from _Robert G. Wilson v_, Aug 08 2001