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A064664 Regard A064413 as giving a permutation of the positive integers; sequence gives inverse permutation. +0
4
1, 2, 5, 3, 10, 4, 14, 8, 6, 9, 20, 7, 28, 13, 11, 17, 33, 12, 37, 18, 15, 19, 43, 16, 24, 27, 22, 26, 57, 23, 61, 31, 21, 32, 25, 30, 67, 36, 29, 40, 74, 35, 81, 41, 39, 42, 89, 45, 50, 46, 34, 47, 100, 48, 53, 49, 38, 56, 107, 52, 115, 60, 51, 64, 54 (list; graph; listen)
OFFSET

1,2

COMMENT

The Mathematica program computes the EKG sequence A064413 and then determines the inverse permutation. - T. D. Noe (noe(AT)sspectra.com), Nov 13 2002

LINKS

J. C. Lagarias, E. M. Rains and N. J. A. Sloane, The EKG sequence, Exper. Math. 11 (2002), 437-446.

Index entries for sequences related to EKG sequence

Index entries for sequences that are permutations of the natural numbers

Eric Weisstein's World of Mathematics, EKG Sequence

EXAMPLE

Original permutation has cycles (1) (2) (3, 4, 6, 9, 10, 5) ( ..., 20, 18, 12, 7, 14, 13, 28, 26, ...) (8) ...

MATHEMATICA

maxN=200; lst={1, 2}; unused=Range[3, maxN]; found=True; While[found, found=False; i=0; While[ !found&&i<Length[unused], i++; If[GCD[lst[[ -1]], unused[[i]]]>1, found=True; AppendTo[lst, unused[[i]]]; unused=Delete[unused, i]]]]; Take[Ordering[lst], unused[[1]]-1]

CROSSREFS

Cf. A064413, A064665-A064669. Equals A064421 + 1.

Sequence in context: A057337 A163233 A096666 this_sequence A078386 A163254 A143121

Adjacent sequences: A064661 A064662 A064663 this_sequence A064665 A064666 A064667

KEYWORD

nonn

AUTHOR

N. J. A. Sloane (njas(AT)research.att.com), Oct 11 2001

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Last modified December 7 08:40 EST 2009. Contains 170430 sequences.


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