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A109216 Smallest factor of 2^(2n+1)+(2n+1)^2. 2

%I #9 Mar 21 2013 13:25:20

%S 3,17,3,3,593,3,3,32993,3,3,2097593,3,3,73,3,3,8589935681,3,3,17,3,3,

%T 11,3,3,83,3,3,11,3,3,17,3,3,857,3,3,71329,3,3,59,3,3,19,3,3,11,3,3,

%U 17,3,3,4561633,3,3,2940725100673,3,3,193,3,3,1867,3,3,17,3,3,44449,3,3,19,3,3

%N Smallest factor of 2^(2n+1)+(2n+1)^2.

%C For n={0, 1, 4, 7, 10, 16, 1003, 1063, 1879, 14677, 17326, 28642, 49534} we have the only primes of the form 2^(2n+1)+(2n+1)^2: A064539. Cases 2n+1 == 1, 2 (mod 3) are trivial and may be omitted.

%H Vincenzo Librandi, <a href="/A109216/b109216.txt">Table of n, a(n) for n = 0..100</a>

%t Table[ With[ {k=2}, FactorInteger[ n^k + k^n]] [[1, 1]], {n, 1, 145, 2}]

%Y Cf. A064539, A109215.

%K base,nonn

%O 0,1

%A _Zak Seidov_, Jun 24 2005

%E More terms from _Robert G. Wilson v_, Jun 24 2005

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