stumped . . . ??

[ibcompton]

i need to setup a formula where a group of every 3 consecutive numbers
will be multiplied by 2.
how is this done (e.g.
1 thru 3 = 6
4 thru 7 = 12
8 thru 11 = 24, etc . . .)?

 

[JimMay]

With Range(A1:A21) containing 1,2,3,4,5,....21
In B1 = enter =IF(MOD(A1,3)=0,A1*2,"") and copy down to B21;
HTH