|
%I #11 Jul 12 2022 13:00:36
%S 3,5,4,5,6,8,9,8,11,10,9,11,8,10,10,10,9,8,10,10,12,11,11,10,11,13,15,
%T 15,14,18,21,19,21,20,19,18,20,20,20,22,21,19,19,21,21,20,16,21,21,20,
%U 21,20,18,18,20,20,19,20,22,19,21,21,17,18,20,21,21,23
%N Number of letters in n-th prime (in English).
%H Michael S. Branicky, <a href="/A049528/b049528.txt">Table of n, a(n) for n = 1..10000</a>
%F a(n) = A005589(A000040(n)) or a(n) = A052360(A000040(n)) depending on whether hyphens and spaces are excluded or included. - _Jonathan Vos Post_, Oct 19 2007
%F a(n) = A005589(A000040(n)) since it does not count spaces or hyphens. - _Michael S. Branicky_, Jul 12 2022
%e a(13) = 8 because 'forty-one' contains 8 letters (not counting the hyphen).
%o (Python)
%o from sympy import nextprime
%o from itertools import count, islice
%o from num2words import num2words as n2w
%o def f(n): return sum(1 for c in n2w(n).replace(" and", "") if c.isalpha())
%o def agen(p=2):
%o while True: yield f(p); p = nextprime(p)
%o print(list(islice(agen(), 68))) # _Michael S. Branicky_, Jul 12 2022
%Y Cf. A000040, A005589, A052360.
%K easy,nice,nonn,word
%O 1,1
%A _G. L. Honaker, Jr._
%E a(66) and beyond from _Michael S. Branicky_, Jul 12 2022
|
