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%I #17 Aug 12 2020 14:42:05
%S 4,8,9,49,64,400,484,900,4096,4489,4900,6084,6400,6889,8000,8464,8649,
%T 9409,9604,40000,40804,44944,48400,64000,64009,66049,68644,69696,
%U 80089,88804,90000,94864,400689,404496,409600,440896,444889,448900,466489
%N Perfect powers using only composite digits 4,6,8,9 and 0.
%C Call terms trivial if they are of the form 10^k*a(m) (e.g., 400,40000,900,90000). Conjecture: sequence has infinitely many nontrivial terms.
%H Charles R Greathouse IV, <a href="/A083807/b083807.txt">Table of n, a(n) for n = 1..10000</a>
%t ppQ[n_]:=GCD@@FactorInteger[n][[All,2]]>1; Select[FromDigits/@ Tuples[{0,4,6,8,9},6],ppQ] (* _Harvey P. Dale_, Aug 12 2020 *)
%o (PARI) list(lim)=my(v=List(),u=[0,4,6,8,9]);forprime(e=2,log(lim+=.5)\log(2), for(b=2,lim^(1/e),if(vecsort(concat(digits(b^e),u),,8)==u,listput(v,b^e)))); vecsort(Vec(v),,8) \\ _Charles R Greathouse IV_, Mar 20 2013
%Y Cf. A083806.
%K base,nonn
%O 1,1
%A _Amarnath Murthy_ and Meenakshi Srikanth (menakan_s(AT)yahoo.com), May 08 2003
%E More terms from Matthew Ohlsen (mjo178(AT)psu.edu), Feb 26 2006
%E Missing terms added by _Charles R Greathouse IV_, Mar 20 2013