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A244255 a(n) = the frequency of the most common 2-digit ending of a prime with n digits. 0

%I

%S 1,6,31,220,1748,14746,127601,1127869,10107163,91579392,837273621

%N a(n) = the frequency of the most common 2-digit ending of a prime with n digits.

%e Of the 3-digit primes, the most common two-digit ending occurs 6 times. Thus a(3) = 6.

%o (Python)

%o import sympy

%o from sympy import isprime

%o def end1(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 ..return max(lst)

%o n = 3

%o while n < 10:

%o ..print(end1(2,n),end=', ')

%o ..n += 1

%Y Cf. A244190.

%K nonn,base,hard,more

%O 2,2

%A _Derek Orr_, Jun 24 2014

%E a(8)-a(12) from _Hiroaki Yamanouchi_, Aug 26 2014

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Last modified October 1 00:02 EDT 2022. Contains 357111 sequences. (Running on oeis4.)