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A169837 EKG sequence started at 3 instead of 2. 16
3, 6, 2, 4, 8, 10, 5, 15, 9, 12, 14, 7, 21, 18, 16, 20, 22, 11, 33, 24, 26, 13, 39, 27, 30, 25, 35, 28, 32, 34, 17, 51, 36, 38, 19, 57, 42, 40, 44, 46, 23, 69, 45, 48, 50, 52, 54, 56, 49, 63, 60, 55, 65, 70, 58, 29, 87, 66, 62, 31, 93, 72, 64, 68, 74, 37, 111, 75, 78, 76, 80, 82, 41 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

A generalization of A064413.

a(n) = A064413(n+1) for n > 43; a(n) = A169849(n) for n > 9. - Reinhard Zumkeller, Jul 04 2014

LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

Gordon Hamilton, The EKG Sequence and the Tree of Numbers

Eric Weisstein's World of Mathematics, EKG Sequence

Index entries for sequences related to EKG sequence

PROG

(Haskell)

import Data.List (delete)

a169837 n = a169837_list !! (n-1)

a169837_list = 3 : ekg 3 (2 : [4..]) where

   ekg x zs = f zs where

       f (y:ys) = if gcd x y > 1 then y : ekg y (delete y zs) else f ys

-- Reinhard Zumkeller, Jul 04 2014

CROSSREFS

Cf. A064413, A064417, A169849.

Sequence in context: A308315 A200474 A154858 * A319513 A160590 A111952

Adjacent sequences:  A169834 A169835 A169836 * A169838 A169839 A169840

KEYWORD

nonn

AUTHOR

T. D. Noe and N. J. A. Sloane, Jun 02 2010

STATUS

approved

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Last modified January 24 13:24 EST 2020. Contains 331193 sequences. (Running on oeis4.)