A244267 a(n) = the frequency of the most common 2-digit ending of a prime < 10^n.

1, 6, 35, 250, 1986, 16716, 144183, 1271765, 11378311, 102956670, 940224567, 8651691637, 80123673992

Offset

2,2

Links

Table of n, a(n) for n=2..14.

Example

Of the primes up to and including the last of the 3-digit primes, the most common 2-digit ending occurs 6 times. Thus a(3) = 6.

Prog

(Python)
import sympy
from sympy import isprime
def prend1(d, n):
..lst = [ ]
..for k in range(10**n):
....if isprime(k):
......lst.append((k%10**d))
..new = 0
..newlst = [ ]
..for i in range(10**(d-1), 10**d):
....new = lst.count(i)
....newlst.append(new)
..return max(newlst)
n = 3
while n < 10:
..print(prend1(2, n), end=', ')
..n += 1

Crossrefs

Cf. A244192.

Sequence in context: A249476 A346922 A355381 * A187443 A325115 A087631

Adjacent sequences: A244264 A244265 A244266 * A244268 A244269 A244270

Keyword

nonn,base,more,hard

Author

Derek Orr, Jun 24 2014

Extensions

a(9)-a(12) from Hiroaki Yamanouchi, Aug 26 2014

Example corrected by Harvey P. Dale, Sep 27 2018

a(13)-a(14) from Giovanni Resta, Oct 23 2018

Status

approved