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 A080544 In binary representation: keep the first digit and rotate right the others twice. 3
 1, 2, 3, 4, 5, 6, 7, 8, 10, 12, 14, 9, 11, 13, 15, 16, 20, 24, 28, 17, 21, 25, 29, 18, 22, 26, 30, 19, 23, 27, 31, 32, 40, 48, 56, 33, 41, 49, 57, 34, 42, 50, 58, 35, 43, 51, 59, 36, 44, 52, 60, 37, 45, 53, 61, 38, 46, 54, 62, 39, 47, 55, 63, 64, 80, 96, 112, 65, 81, 97, 113, 66 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS a(n) = A080542(A080542(n)); permutation of natural numbers with inverse = A080543: A080543(a(n))=a(A080543(n))=n. LINKS Ivan Neretin, Table of n, a(n) for n = 1..8192 FORMULA a(n) = n - 3*A053645(A002265(n)) + (2^(A000523(n)-2)-1)*A010873(n) for n >= 4. - Robert Israel, Sep 01 2015 EXAMPLE a(20)=a('10100')='10001'=17; a(25)=a('11001')='10110'=22. MAPLE f:= proc(n) local m, a;      m:= ilog2(n);      a:= n mod 4;      (n - a - 2^m)/4 + 2^(m-2)*a+2^m end proc: f(2):= 2: map(f, [\$1..100]); # Robert Israel, Sep 01 2015 MATHEMATICA Table[FromDigits[Prepend[RotateRight[Rest[IntegerDigits[n, 2]], 2], 1], 2], {n, 72}] (* Ivan Neretin, Aug 30 2015 *) CROSSREFS Sequence in context: A270189 A257672 A285314 * A178878 A175326 A018676 Adjacent sequences:  A080541 A080542 A080543 * A080545 A080546 A080547 KEYWORD nonn,base AUTHOR Reinhard Zumkeller, Feb 20 2003 STATUS approved

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Last modified May 29 01:41 EDT 2022. Contains 354122 sequences. (Running on oeis4.)