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Problems
Contests
National and Regional Contests
Ukraine Contests
Official Ukraine Selection Cycle
Ukraine Team Selection Test
2013 Ukraine Team Selection Test
11
11
Part of
2013 Ukraine Team Selection Test
Problems
(1)
infinite primes p divide 2^{2^n} + a
Source: Ukraine TST 2013 p11
4/28/2020
Specified natural number
a
a
a
. Prove that there are an infinite number of prime numbers
p
p
p
such that for some natural
n
n
n
the number
2
2
n
+
a
2^{2^n} + a
2
2
n
+
a
is divisible by
p
p
p
.
number theory
primes
Divisibility