

A064664


Regard A064413 as giving a permutation of the positive integers; sequence gives inverse permutation.


21



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, 59, 128, 65, 44, 55
(list;
graph;
refs;
listen;
history;
text;
internal format)



OFFSET

1,2


COMMENTS

The Mathematica program computes the EKG sequence A064413 and then determines the inverse permutation.  T. D. Noe, Nov 13 2002


LINKS

T. D. Noe and Ray Chandler, Table of n, a(n) for n = 1..10000 (first 1000 terms from T. D. Noe)
J. C. Lagarias, E. M. Rains and N. J. A. Sloane, The EKG sequence, Exper. Math. 11 (2002), 437446.
Eric Weisstein's World of Mathematics, EKG Sequence
Index entries for sequences related to EKG sequence
Index entries for sequences that are permutations of the natural numbers


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]


PROG

(Haskell)
import Data.List (elemIndex); import Data.Maybe (fromJust)
a064664 = (+ 1) . fromJust . (`elemIndex` a064413_list)
 Reinhard Zumkeller, May 01 2014, Sep 17 2011


CROSSREFS

Cf. A064413, A064665A064669. Equals A064421 + 1.
Sequence in context: A163233 A096666 A191855 * A078386 A163254 A277696
Adjacent sequences: A064661 A064662 A064663 * A064665 A064666 A064667


KEYWORD

nonn


AUTHOR

N. J. A. Sloane, Oct 11 2001


STATUS

approved



