OFFSET
1,1
COMMENTS
A letter with a diaeresis (for example 5 = "fünf" (not "fuenf")) or with an "ß" (in 30 = "dreißig" (not "dreissig")) is still counted as a single letter.
FORMULA
EXAMPLE
a(1) = 4 because the first prime is 2, and it has in the German language (zwei) 4 letters.
CROSSREFS
KEYWORD
nonn,word
AUTHOR
Ivan Panchenko, Aug 27 2009
EXTENSIONS
a(11), a(12) corrected and more terms by Georg Fischer, Dec 19 2020
STATUS
approved