Dear all,

     Thanks for all your constructive and nice advice in advance ^)^

      I will state my problem once again  in more details ...all the problems we discussing is about digit and independent of  letter . different letter is just stand for different digit...

      Question : ABC-ABD-ABE is a 9 bit numeric string( A B C D E are different dgit, C D E must be sequential and sort ascending) , just like 124125126 , 253254255 ,192193194 ,384385386 ,781782783 and so on .

 Many thanks and best regards,

Sparky