A069659 => A061433 ?

[Hans Havermann]

N. J. A. Sloane wrote:

> Maybe someone will now compute more terms and find out when they  
> first differ!
> These may be good candidates for b-files.

> %S A061433  
> 9,81,961,9801,99856,998001,9998244,99980001,999950884,9999800001,
> %T A061433  
> 99999515529,999998000001,9999995824729,99999980000001,999999961946176,
> %U A061433 9999999800000001,99999999989350756,999999998000000001
> %N A061433 Largest n-digit square.
> %C A061433 When (if ever) does this differ from A069659?

> %S A069659  
> 9,81,961,9801,99856,998001,9998244,99980001,999950884,9999800001,
> %T A069659  
> 99999515529,999998000001,9999995824729,99999980000001,999999961946176,
> %U A069659 9999999800000001,99999999989350756,999999998000000001
> %N A069659 Largest n-digit perfect power.
> %C A069659 Are there terms which are not perfect squares? In other  
> words, when (if ever) does this differ from A061433.

Trivially, 81 is both a square and a fourth power. Assuming my  
program works, there are no differences in the first 1500 terms.