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%I #7 Mar 11 2014 01:32:50
%S 1,2,3,5,4,6,9,8,7,10,14,11,12,13,16,18,15,17,23,19,20,21,22,25,24,26,
%T 27,33,28,29,30,31,36,32,34,35,37,38,39,40,41,43,45,42,51,44,46,47,48,
%U 49,50,52,53,55,54,56,57,58,59,60,61,62,63,64,65,66,67,68,73,69,78,70
%N a(1)=1. For n >= 2, if A025474(n) is the exponent of the n-th prime-power (1 is considered the first prime-power here), then a(n) = the A025474(n)th integer from among those positive integers not yet in the sequence.
%C This sequence is a permutation of the positive integers.
%e 9 is the 8th power of a prime. 9 = 3^2. So we want the 2nd integer (because 2 is the exponent) from among those positive integers not in the first 7 terms of the sequence. The first 7 terms are 1,2,3,5,4,6, 9. Those positive integers not yet appearing form the infinite sequence 7,8,10,11,12,13,14,15,16... The 2nd integer not yet occurring is 8. So a(9)=8.
%Y Cf. A025474.
%K nonn
%O 1,2
%A _Leroy Quet_, Feb 11 2010
%E Extended by _Ray Chandler_, Mar 10 2010