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Least prime factor of n^n + (n+1)^(n+1).
5

%I #32 Aug 15 2019 06:48:57

%S 2,5,31,283,3,67,11,11,5,173,3,1237,7,31,7334881,227,3,773,149,47,11,

%T 5,3,101,13,73,151,349,3,4421,107,191,17,7,3,17,19,624808693,2273,

%U 25788481,3,5,59,1752761753,23,2144707,3,49547,5,275851515609829434269,19,919,3,13,7,107,29

%N Least prime factor of n^n + (n+1)^(n+1).

%H Hugo Pfoertner, <a href="/A056187/b056187.txt">Table of n, a(n) for n = 0..234</a>, (first 96 terms from Chai Wah Wu).

%H factordb.com, <a href="http://factordb.com/index.php?query=235%5E235%2B236%5E236">Status of 235^235+236^236</a>.

%H Walter Nissen, <a href="http://upforthecount.com/math/nnpomega.html">np(n) = n^n + (n+1)^(n+1) -- 2 prominent questions</a>. (Updated Oct 02 2012)

%F a(n) = A020639(A056788(n+1)). - _M. F. Hasler_, Oct 04 2012

%e a(5) = 67 because 5^5 + 6^6 = 3125 + 46656 = 67 * 743.

%o (PARI) A056187(n)=factor((n+1)^(n+1)+n^n)[1,1] \\ _M. F. Hasler_, Oct 04 2012

%Y Cf. A056788, A056790, A192397, A217435.

%K nonn

%O 0,1

%A _Walter Nissen_, Aug 20 2000

%E 2 added by _Arkadiusz Wesolowski_, Jun 30 2011

%E a(53)-a(56) from _Chai Wah Wu_, Jul 22 2019