%I #16 Nov 25 2019 01:01:07
%S 0,0,16,11,23,25,28,33,31,45,10,46,61,60,66,62,66,73,76,76,20,76,91,
%T 116,109,105,122,125,105,121,29,130,115,132,132,164,153,159,162,152,
%U 39,178,182,163,181,174,186,195,180,204,45,179,221,217,224,225,245,215,208,252,55,215
%N Least k such that some digit occurs n times (or more) in the decimal representation of n^k.
%C a(10^j) = ceiling((10^j) / j) for any j > 0.
%C a(i*10^j) <= ceiling((i*10^j) / j) for any i > 0 and j > 0.
%H Paul Tek, <a href="/A225842/b225842.txt">Table of n, a(n) for n = 0..1000</a>
%e 3^11 = 177147 is the first power of 3 with some digit occurring 3 times in its decimal representation. Hence a(3)=11.
%t a[n_] := If[n < 2, 0, Block[{k = 1}, While[Max[DigitCount[n^k]] < n, k++]; k]]; Array[a, 62, 0] (* _Giovanni Resta_, May 17 2013 *)
%o (PARI) mddo(n)=my(c=vector(10),m=0,d);while(n>0,d=n%10;n=n\10;c[d+1]=1+c[d+1];m=max(c[d+1],m));return(m)
%o a(n)=my(k=0,p=1);while(mddo(p)<n,k=k+1;p=p*n);return(k)
%K nonn,base
%O 0,3
%A _Paul Tek_, May 16 2013