OFFSET
1,2
COMMENTS
The sum of 1/n where n has a single 0 in base 2.
LINKS
Robert Baillie, Summing The Curious Series Of Kempner And Irwin, arXiv:0806.4410 [math.CA], 2008-2015.
FORMULA
Equals Sum_{n>=2} Sum_{k=0..n-2}, 1/(2^n - 1 - 2^k).
EXAMPLE
1.4625907350443646995461454467205346210747448647488211093642006243545229...
MATHEMATICA
RealDigits[ N[ Sum[1/(2^n - 1 - 2^k), {n, 2, 400}, {k, 0, n - 2}], 111]][[1]]
(* first install irwinSums.m, see reference, then *) First@ RealDigits@ iSum[0, 1, 111, 2] (* Robert G. Wilson v, Aug 03 2010 *)
CROSSREFS
KEYWORD
AUTHOR
Robert G. Wilson v, May 15 2009
STATUS
approved