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 A080543 In binary representation: keep the first digit and rotate left the others twice. 3

%I

%S 1,2,3,4,5,6,7,8,12,9,13,10,14,11,15,16,20,24,28,17,21,25,29,18,22,26,

%T 30,19,23,27,31,32,36,40,44,48,52,56,60,33,37,41,45,49,53,57,61,34,38,

%U 42,46,50,54,58,62,35,39,43,47,51,55,59,63,64,68,72,76,80,84,88,92,96

%N In binary representation: keep the first digit and rotate left the others twice.

%C a(n) = A080541(A080541(n)); permutation of natural numbers with inverse = A080544: A080544(a(n)) = a(A080544(n)) = n.

%H Ivan Neretin, <a href="/A080543/b080543.txt">Table of n, a(n) for n = 1..8192</a>

%H <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a>

%e a(20) = a('10100') = '100001' = 17; a(24) = a('11000') = '10010' = 18.

%t Table[FromDigits[Prepend[RotateLeft[Rest[IntegerDigits[n, 2]], 2], 1], 2], {n, 72}] (* _Ivan Neretin_, Aug 30 2015 *)

%Y Cf. A080541, A080544.

%K nonn,base

%O 1,2

%A _Reinhard Zumkeller_, Feb 20 2003

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Last modified May 19 17:07 EDT 2022. Contains 353847 sequences. (Running on oeis4.)