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%I #6 Mar 30 2012 18:50:25
%S 0,0,0,0,0,0,0,1,0,0,1,0,0,1,3,0,0,1,0,3,0,1,1,1,1,1,4,0,3,2,2,1,0,0,
%T 1,4,2,4,1,2,2,3,0,1,6,1,1,0,6,2,7,3,1,4,1,1,2,8,3,1,0,1,1,6,1,1,9,1,
%U 5,0,5,4,1,3,0,5,1,0,10,1,3,2,12,11,2,1,1,3
%N Number of perfect powers between two successive nonprime prime powers.
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/PerfectPower.html">Perfect Power</a>.
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/PrimePower.html">Prime Power</a>.
%e There are three perfect powers with composite roots between A025475(15)=169=13^2 and A025475(15+1)=243=3^5: 196=(2*7)^2, 216=3^5 and 225=(3*5)^2; therefore a(15)=3.
%e a(16)=0, since there are no perfect powers between A025475(16)=243=3^5 and A025475(16+1)=256=2^8.
%Y Cf. A001597, A025475.
%K nonn
%O 1,15
%A _Reinhard Zumkeller_, Oct 10 2002
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