a(1) = 1; a(n) = smallest nontrivial n-th power with property that digits alternate in parity individually as well as in concatenation with previous terms.

1

%I

%S 1,4,125,81

%N a(1) = 1; a(n) = smallest nontrivial n-th power with property that digits alternate in parity individually as well as in concatenation with previous terms.