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%I #5 Dec 05 2013 19:55:52
%S 9,81,841,8649,64009,0,4004001,0,900000000,0,40000400001,0,
%T 9000000000000,0,400000040000001,0,90000000000000000,0,
%U 4000000004000000001,0,900000000000000000000,0,40000000000400000000001
%N Largest n-digit square which leaves a square at every step if most significant digit and least significant digit are deleted until a one- or two-digit square is obtained. a(2n) = 0 if no such square exists. a(2n+1) = 9*10^2n only if no nontrivial candidate exists.
%F Beginning with term a(6) the following pattern applies: a(4k)=0; a(4k+1)=9*10^4k=(3*10^2k)^2; a(4k+2)=0; a(4k+3)=(2*10^(2k+1)+1)^2. - _Ray Chandler_, Aug 03 2003
%e a(5) = 64009 as 64009, 400 and 0 all are squares. Though 90000 is a candidate, it is a trivial one.
%Y Cf. A077485.
%K base,nonn
%O 1,1
%A _Amarnath Murthy_, Nov 07 2002
%E More terms from _Ray Chandler_, Aug 03 2003
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