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A244255 a(n) = the frequency of the most common 2-digit ending of a prime with n digits. 0
1, 6, 31, 220, 1748, 14746, 127601, 1127869, 10107163, 91579392, 837273621 (list; graph; refs; listen; history; text; internal format)
OFFSET

2,2

LINKS

Table of n, a(n) for n=2..12.

EXAMPLE

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

PROG

(Python)

import sympy

from sympy import isprime

def end1(d, n):

..lst = []

..for k in range(10**(d-1), 10**d):

....num = ''

....count = 0

....for i in range(10**(n-d-1), 10**(n-d)):

......if isprime(int(str(i)+str(k))):

........count += 1

....lst.append(count)

..return max(lst)

n = 3

while n < 10:

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

..n += 1

CROSSREFS

Cf. A244190.

Sequence in context: A121754 A351818 A200775 * A299550 A208594 A318539

Adjacent sequences:  A244252 A244253 A244254 * A244256 A244257 A244258

KEYWORD

nonn,base,hard,more

AUTHOR

Derek Orr, Jun 24 2014

EXTENSIONS

a(8)-a(12) from Hiroaki Yamanouchi, Aug 26 2014

STATUS

approved

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Last modified August 8 14:59 EDT 2022. Contains 356009 sequences. (Running on oeis4.)