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Numbers whose square has a square number of decimal digits.
1

%I #20 Apr 23 2013 11:14:18

%S 0,1,2,3,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,

%T 52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,

%U 75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94

%N Numbers whose square has a square number of decimal digits.

%e 32^2 is 1024, which has 2^2 = 4 digits.

%o (R) sq=(1:10)^2; sqsqd=c(); i=0; while(length(sqsqd)<500) { if(floor(log10(i^2)+1)%in%sq) sqsqd=c(sqsqd,i); i=i+1 }

%Y Cf. A000290, A179935.

%K nonn,easy,base

%O 1,3

%A _Kevin L. Schwartz_ and _Christian N. K. Anderson_, Mar 23 2013