%I #18 Jul 27 2018 08:46:44
%S 25,225,22201,2002225,21022225,212722225,11222224225,132922222225,
%T 12222722202201,22222220262025,1222522204222225,22292262226224225,
%U 2222262262926922225,22226224222205212225,2222222222222640225,22222262422274682222225,1222212242622225512222224,2220022223125222222222201
%N Smallest square containing exactly n 2's.
%C a(21) > 10^28. - _Giovanni Resta_, Jul 27 2018
%H Giovanni Resta, <a href="/A036509/b036509.txt">Table of n, a(n) for n = 1..20</a>
%F a(n) = A048347(n)^2. - _Max Alekseyev_, Oct 20 2008
%t a[n_] := Block[{k=1}, While[DigitCount[k^2, 10, 2] != n, k++]; k^2]; Array[a, 7] (* _Giovanni Resta_, Jul 27 2018 *)
%Y Cf. A048347. - _Jon E. Schoenfield_, Jan 24 2009
%K nonn,base
%O 1,1
%A _David W. Wilson_
%E a(13)-a(15) from _Max Alekseyev_, Oct 20 2008, Nov 10 2008, Dec 05 2008
%E a(16)-a(18) from _Jon E. Schoenfield_, Dec 25 2008