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Composites of the form 2^(2^k)+3.
1

%I #14 Sep 18 2024 11:20:44

%S 259,4294967299,18446744073709551619,

%T 340282366920938463463374607431768211459,

%U 115792089237316195423570985008687907853269984665640564039457584007913129639939

%N Composites of the form 2^(2^k)+3.

%D D. M. Burton, Elementary Number Theory, Allyn and Bacon, Inc., Boston, MA, 1976, p. 238.

%H Harry J. Smith, <a href="/A063485/b063485.txt">Table of n, a(n) for n = 1..8</a>

%o (PARI) for(n=0,8,my(x=(2^(2^n)+3)); if(!isprime(x),print1(x, ", ")))

%K nonn

%O 1,1

%A _Jason Earls_, Jul 28 2001

%E Offset changed by _Andrew Howroyd_, Sep 18 2024