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A077485 a(1) = 1, then smallest 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 digit square is obtained. a(2n) = 0 if no such square exists. a(2n+1) = 10^2n only if no nontrivial candidate exists. 2

%I

%S 1,16,144,1369,10816,0,1004004,0,100000000,0,10000400004,0,

%T 1000000000000,0,100000040000004,0,10000000000000000,0,

%U 1000000004000000004,0,100000000000000000000,0,10000000000400000000004

%N a(1) = 1, then smallest 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 digit square is obtained. a(2n) = 0 if no such square exists. a(2n+1) = 10^2n only if no nontrivial candidate exists.

%F Beginning with term a(6) the following pattern applies: a(4k)=0; a(4k+1)=10^4k=(10^2k)^2; a(4k+2)=0; a(4k+3)=(10^(2k+1)+2)^2. - _Ray Chandler_, Aug 03 2003

%e a(3) = 144 as 144 and 4 are both squares.

%e a(4) = 1369 as 1369 and 36 are both squares.

%Y Cf. A077486.

%K base,nonn

%O 1,2

%A _Amarnath Murthy_, Nov 07 2002

%E Corrected and extended by _Ray Chandler_, Aug 03 2003

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Last modified January 24 13:48 EST 2022. Contains 350538 sequences. (Running on oeis4.)