All the positive integers starting with 1 are considered in ascending order of magnitude – and spelled out in conformity with the American system
, but disregarding hyphens, spaces, commas and, the word "and" - resulting in this infinite string:
Determine the 2010th letter in the above pattern. What is the 20100th letter in the above pattern?
I have followed the link, but do not find that posting conclusive, let alone authoritative. I was aware of the billion/milliard matter but surely those are not reached by 20K cardinal numbers (well under one million letters). The issue of including "and" (and spaces and punctuations) is avoided by this puzzle's wording.
In any case, that reference did not give guidance on how 1101 would be written in letters (which is certainly in range for this puzzle).
I am sure "eleven hundred one" would be much more common than "one thousand one hundred one" in ordinary parlance. I acknowledged organization (organisation?) style sheets might show preferences, but these have no generic authority as "American". Perhaps all Brits agree on some transcription, but I am not aware of an Academie to resolve such. I never could see how "colour" and "metre" followed pronunciation, but Yankees and Brits can agree on such matters to announce "laissez-faire laissez-aller" -- or Churchill's bon mot of two nations divided by a common language. (I cannot discern the home base of perplexus, since it seems to follow a time stamp unique to itself -- lunar perhaps.)