%N Smallest prime p of three consecutive primes such that the sum of their n-th powers is prime, or 0 if such a prime does not exist.
%C Let p = prime(i), q = prime(i+1), r = prime(i+2).
%C (*) p^n + q^n + r^n has to be a prime.
%C When n is even and p > 3, then (*) is composite because primes greater than 3 are either of form 6k-1 or 6k+1 for some k. Hence, squares (or any even power) of such a prime has the form 6k+1. Adding three such even powers will produce a number of the form 6k+3, which is divisible by 3.
%C When n is even and p = 3, sequence A160773 gives the even n for which 3^n + 5^n + 7^n is prime.
%e 5 + 7 + 11 = 23 = prime(9); 3^2 + 5^2 + 7^2 = 83 = prime(23); 23^3 + 29^3 + 31^3 = 66347 = prime(6616).
%Y A133530, A133531, A133532, A133533, A160773
%A Ulrich Krug (leuchtfeuer37(AT)gmx.de), Apr 21 2010
%E a(0) term added by _T. D. Noe_, Nov 23 2010