%I A086712
%S A086712 0,1,2,2,3,3,3,4,3,4,6,6,5,5,7,8,5,6,6,7,6,8,6,8,8,7,8,10,10,9,8,9,14,
               8,
%T A086712 10,11,10,12,8,11,8,12,13,12,11,11,13,13,13,13,13,11,11,14,11,13,16,12,
%U A086712 16,14,15,16,17,13,16,15,12,18,27,15,19,18,17,15,16,15,13,18,17,15
%N A086712 Number of times the n-th prime power can be written as an arithmetic 
               mean of two other prime powers.
%H A086712 Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/
               PrimePower.html">Prime Power</a>
%e A086712 n=7, A000961(7)=8=2^3: (3+13)/2=(A000961(3)+A000961(10))/2, (5+11)/2=(A000961(5)+A000961(9))/
               2 and (7+3^2)/2=(A000961(6)+A000961(8))/2: therefore a(7)=3.
%Y A086712 Cf. A000961, A071681.
%Y A086712 Sequence in context: A134674 A000121 A049846 this_sequence A125842 A029865 
               A072644
%Y A086712 Adjacent sequences: A086709 A086710 A086711 this_sequence A086713 A086714 
               A086715
%K A086712 nonn
%O A086712 1,3
%A A086712 Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Aug 01 2003