OFFSET
1,2
COMMENTS
This sequence is a permutation of the positive integers.
EXAMPLE
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.
CROSSREFS
KEYWORD
nonn
AUTHOR
Leroy Quet, Feb 11 2010
EXTENSIONS
Extended by Ray Chandler, Mar 10 2010
STATUS
approved