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A080543
In binary representation: keep the first digit and rotate left the others twice.
3
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, 30, 19, 23, 27, 31, 32, 36, 40, 44, 48, 52, 56, 60, 33, 37, 41, 45, 49, 53, 57, 61, 34, 38, 42, 46, 50, 54, 58, 62, 35, 39, 43, 47, 51, 55, 59, 63, 64, 68, 72, 76, 80, 84, 88, 92, 96
OFFSET
1,2
COMMENTS
a(n) = A080541(A080541(n)); permutation of natural numbers with inverse = A080544: A080544(a(n)) = a(A080544(n)) = n.
EXAMPLE
a(20) = a('10100') = '100001' = 17; a(24) = a('11000') = '10010' = 18.
MATHEMATICA
Table[FromDigits[Prepend[RotateLeft[Rest[IntegerDigits[n, 2]], 2], 1], 2], {n, 72}] (* Ivan Neretin, Aug 30 2015 *)
CROSSREFS
Sequence in context: A246025 A211699 A118600 * A285916 A119797 A032972
KEYWORD
nonn,base
AUTHOR
Reinhard Zumkeller, Feb 20 2003
STATUS
approved