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A185949 Smallest prime ending in 10^n+1 in its base-10 representation. 1
11, 101, 21001, 1810001, 2100001, 61000001, 2010000001, 11100000001, 61000000001, 1810000000001, 14100000000001, 151000000000001, 5010000000000001, 9100000000000001, 271000000000000001, 1110000000000000001, 24100000000000000001, 261000000000000000001, 3910000000000000000001, 11100000000000000000001 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
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}]
PROG
(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(num)):
print(num)
break
CROSSREFS
Sequence in context: A199304 A156668 A103992 * A001387 A358198 A247863
KEYWORD
nonn,base
AUTHOR
Amir H. Farrahi, Feb 07 2011
STATUS
approved

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Last modified May 20 05:07 EDT 2024. Contains 372703 sequences. (Running on oeis4.)