[seqfan] Erroneous formula in A087690

[israel at math.ubc.ca]

A087690 is Denominators of successive partial sums of sum(1/(2^n-1)). 
The formula given, a(n) = lcm(a(n-1), 2^n-1), is obviously wrong, e.g.
a(4) = 35 is not a multiple of a(3) = 21.
I can add a Maple program for this and A087689, and b-files.  What's the 
limit on sizes of numbers in b-files?  a(104) has 1002 digits already.

Robert Israel
University of British Columbia