We have: 891=0.01123595...
The decimal is formed like this:
. . 0.01
. . 0.001
. . 0.0002
. . 0.00003
. . 0.000005
. . 0.0000008
. . 0.00000013
. . 0.000000021
. . 0.0000000034
. . . . . . ⋮
It seems that: 101n=1∑∞10nFn=891
. . where Fn is the nth Fibonacci number.
Care to prove it?