A185949 Smallest prime ending in 10^n+1 in its base-10 representation.

11, 101, 21001, 1810001, 2100001, 61000001, 2010000001, 11100000001, 61000000001, 1810000000001, 14100000000001, 151000000000001, 5010000000000001, 9100000000000001, 271000000000000001, 1110000000000000001, 24100000000000000001, 261000000000000000001, 3910000000000000000001, 11100000000000000000001

Offset: 1

Author

Amir H. Farrahi, Feb 07 2011

Keywords

• nonn
• base

Links

• Robert Israel, Table of n, a(n) for n = 1..995

Programs

Maple

f:= proc(n) local p;
  for p from 10^n+1 by 10^(n+1) do
    if isprime(p) then return p fi
  od
end proc:
map(f, [$1..30]); # Robert Israel, May 03 2018

Mathematica

Table[k=0; While[!PrimeQ[p=FromDigits[Join[IntegerDigits[k], IntegerDigits[10^n+1]]]], k++]; p, {n,20}]

Python

from sympy import isprime as is_prime
# This implementation assumes function is_prime(n)
# returns True if n is prime, or False otherwise:
for n in range (1, 100):
    pattern = 10**n + 1
    for j in range (0, 10000000):
        if (j == 0):
            num = "%d" % (pattern)
        else:
            num = "%d%d" % (j, pattern)
        if (is_prime(int(num))):
            print(num)
            break