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%I #6 Mar 30 2012 18:50:19
%S 2,4,1,6,3,8,5,7,9,10,11,12,13,15,17,14,19,16,21,23,25,18,27,29,31,33,
%T 35,20,37,22,39,41,43,45,47,24,49,51,53,26,55,28,57,59,61,30,63,65,67,
%U 69,71,32,73,75,77,79,81,34,83,36,85,87,89,91,93,38,95,97,99,40,101,42
%N a(n) = if n+1 is prime then A049084(n+1)*2 else A066246(n+1)*2 - 1.
%C Permutation of natural numbers; inverse: A066249.
%H <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a>
%F a(n) = A026238(n+1)*2 - A066247(n+1).
%Y Cf. A066249, A049084, A066246, A026238, A066247, A066250, A066252.
%K nonn
%O 1,1
%A _Reinhard Zumkeller_, Dec 09 2001