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%I #2 Mar 30 2012 17:35:35
%S 1,2,3,4,5,6,7,8,9,10,11,20,22,30,33,40,44,50,55,60,66,70,77,80,88,90,
%T 99,100,110,111,112,114,120,130,133,154,170,175,200,210,220,222,224,
%U 228,240,260,266,267,298,300,310,315,330,333,336,340,360,372,376,390,399
%N Numbers n such that r*n*n/k is an integer. n=(x_1 x_2 ... x_r) where x_i are digits of n, k = x_1^2 + x_2^2 + ... + x_r^2.
%e n=715, r=3, 715*715*3/(7*7+1*1+5*5)=20449, n=715 belongs to the sequence.
%Y Cf. A005349
%K base,easy,nonn
%O 1,2
%A _Ctibor O. Zizka_, Sep 07 2010