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%I #28 Jul 11 2014 09:10:11
%S 0,3,7,3,7,3,7,7,3,3,1,7,3,7
%N a(n) = most common final digit for a prime with n digits, or 0 if there is a tie.
%e Primes with two digits are {11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97}. The most frequent last digit is a 3. Thus a(2) = 3.
%o (Python)
%o import sympy
%o from sympy import isprime
%o def end(d,n):
%o ..lst = []
%o ..for k in range(10**(d-1),10**d):
%o ....num = ''
%o ....count = 0
%o ....for i in range(10**(n-d-1),10**(n-d)):
%o ......if isprime(int(str(i)+str(k))):
%o ........count += 1
%o ....lst.append(count)
%o ..a = max(lst)
%o ..lst[lst.index(a)] = 0
%o ..b = max(lst)
%o ..if a == b:
%o ....return 0
%o ..else:
%o ....return max(a,b) + 10**(d-1)
%o n = 2
%o while n < 10:
%o ..print(end(1,n),end=', ')
%o ..n += 1
%Y Cf. A244190.
%K nonn,base,hard,more
%O 1,2
%A _Derek Orr_, Jun 22 2014
%E a(9)-a(14) from _Hiroaki Yamanouchi_, Jul 10 2014
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