Formula to highlight error in a sequence

[alexis bissonnette]

Hi,

I am looking for a formula to find and highlight an error in a sequence that have characters and numbers:

For exemple:

A0005551

A0005552

A0005553

A0005564 (error in the sequence)

A0005555

...

Thank you for your help

[#2]

Alexis,

based on your sample.

=IF(SUBSTITUTE(A2,"A",)-SUBSTITUTE(A1,"A",)=1,"","ERROR")

[#3]

Thanks a lot, it works well!