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a(1) = 1, then a(n) is the smallest number such that a(a(n)) = 2n+1.
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%I #30 Jul 15 2022 06:54:59

%S 1,3,5,6,7,9,11,10,13,17,15,14,19,25,23,18,21,33,27,22,35,41,31,26,29,

%T 49,39,30,51,57,47,34,37,65,43,38,67,73,55,42,45,81,71,46,83,89,63,50,

%U 53,97,59,54,99,105,79,58,61,113,103,62,115

%N a(1) = 1, then a(n) is the smallest number such that a(a(n)) = 2n+1.

%C Original name was "Similar to A079905, but without the 'monotonically increasing sequence' condition."

%H Yifan Xie, <a href="/A169957/b169957.txt">Table of n, a(n) for n = 1..10000</a> (first 499 terms from Charlie Neder)

%F a(1) = 1, a(2) = 3, a(4k) = 4k + 2, all other terms follow from the criterion defining the sequence. - _Charlie Neder_, Dec 21 2018

%Y Cf. A080653, A079905, A169956.

%K nonn,easy,look

%O 1,2

%A _Eric Angelini_, Aug 02 2010

%E a(25)-a(61) from _Charlie Neder_, Dec 21 2018

%E Name changed by _Charlie Neder_, Dec 22 2018