%I A075773
%S A075773 3,4,7,9,9,5,5,13,15,17,19,21,21,4,16,25,27,27,20,18,18,33,35,35,19,39,
%T A075773 41,43,43,28,47,49,51,53,55,57,59,61,61
%N A075773 Let {b(n)} be the sequence of perfect powers (A001597); then a(n) = max 
               { b(n)-b(n-1), b(n+1)-b(n) }.
%e A075773 The perfect powers are 1, 4, 8, 9, 16, 25, 27, 32, 36, 49, 64, 81, 100, 
               121, etc. The 7th is 27. This is 2 larger than the 6th (25) and 5 
               smaller than the 8th (32). So a(7)=5.
%Y A075773 Cf. A001597, A053289, A075772.
%Y A075773 Sequence in context: A117587 A130420 A101715 this_sequence A087276 A138225 
               A114889
%Y A075773 Adjacent sequences: A075770 A075771 A075772 this_sequence A075774 A075775 
               A075776
%K A075773 nonn
%O A075773 1,1
%A A075773 N. Fernandez (primeness(AT)borve.org), Oct 09 2002