A162487 - OEIS

%I #6 Mar 03 2020 21:04:17

%S 2,2,2,2,2,5,3,15,7,33,8,9,21,34,9,56,80,32,67,97,65,45,36,133,98,51,

%T 9,76,20,8,157,87,200,214,2,20,91,2,111,122,5,247,142,56,98,342,184,

%U 289,21,364,32,2,365,423,34,91,157,329,441,234,234,98,87,291,513

%N Values of y for A094133: primes of the form x^y + y^x, x > y > 1.

%C See A094133 for links, references and more information.

%C Whereas a list of the possible x-values can be established by a brute-force search, this is not possible for the y-values. Some, however, may easily be excluded. For example, 4 cannot occur in this sequence, since for even y, x must be odd, and for x = 2k - 1, x^4 + 4^x = (x^2 + 2^k*x + 2^x)(x^2 - 2^k*x + 2^x).

%F A094133(n) = A162486(n)^A162487(n) + A162487(n)^A162486(n).

%K nonn

%O 1,1

%A _M. F. Hasler_, Jul 04 2009

%E More terms from _Jinyuan Wang_, Mar 03 2020