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.

A077486

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.