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A244191 a(n) = most common final digit for a prime < 10^n, or 0 if there is a tie.

%I A244191 #33 May 22 2025 10:21:39
%S A244191 0,3,7,3,7,3,3,7,3,3,7,7,3,3
%N A244191 a(n) = most common final digit for a prime < 10^n, or 0 if there is a tie.
%H A244191 <a href="/index/Fi#final">Index entries for sequences related to final digits of numbers</a>
%e A244191 For all 25 primes < 100 (10^2), we see that the last digit that appears the most is 3. Thus a(2) = 3.
%o A244191 (Python)
%o A244191 import sympy
%o A244191 from sympy import isprime
%o A244191 def prend(d,n):
%o A244191   lst = []
%o A244191   for k in range(10**n):
%o A244191     if isprime(k):
%o A244191       lst.append((k%10**d))
%o A244191   new = 0
%o A244191   newlst = []
%o A244191   for i in range(10**(d-1),10**d):
%o A244191     new = lst.count(i)
%o A244191     newlst.append(new)
%o A244191   newlst1 = newlst.copy()
%o A244191   a = max(newlst1)
%o A244191   newlst1[newlst1.index(a)] = 0
%o A244191   b = max(newlst1)
%o A244191   if a == b:
%o A244191     return 0
%o A244191   else:
%o A244191     return newlst.index(max(a,b)) + 10**(d-1)
%o A244191 n = 2
%o A244191 while n < 10:
%o A244191   print(prend(1,n),end=', ')
%o A244191   n += 1
%Y A244191 Cf. A007652, A095178, A244192.
%K A244191 nonn,base,hard,more
%O A244191 1,2
%A A244191 _Derek Orr_, Jun 22 2014
%E A244191 a(9)-a(14) from _Hiroaki Yamanouchi_, Sep 27 2014