The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A064421

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A064421

Term at which n appears in A064413 (if it begins at 2).
(history; published version)

#9 by Susanna Cuyler at Thu Aug 30 22:40:35 EDT 2018

STATUS

reviewed

approved

#8 by Joerg Arndt at Thu Aug 30 11:08:30 EDT 2018

STATUS

proposed

reviewed

#7 by Jean-François Alcover at Thu Aug 30 10:20:26 EDT 2018

STATUS

editing

proposed

#6 by Jean-François Alcover at Thu Aug 30 10:20:18 EDT 2018

MATHEMATICA

terms = 100;

ekg[s_] := Block[{m = s[[-1]], k = 3}, While[MemberQ[s, k] || GCD[m, k] == 1, k++]; Append[s, k]];

EKG = Nest[ekg, {2, 4}, 2 terms];

a[1] = 0; a[n_] := FirstPosition[EKG, n] // First;

Array[a, terms] (* Jean-François Alcover, Aug 30 2018, after Robert G. Wilson v *)

STATUS

approved

editing

#5 by Russ Cox at Sat Mar 31 13:50:42 EDT 2012

EXTENSIONS

More terms from _Naohiro Nomoto (n_nomoto(AT)yabumi.com), _, Sep 30 2001

Discussion

Sat Mar 31

13:50

OEIS Server: https://oeis.org/edit/global/907

#4 by Russ Cox at Sun Jul 10 18:43:27 EDT 2011

LINKS

<a href="/Sindx_index/Ed.html#EKG">Index entries for sequences related to EKG sequence</a>

Discussion

Sun Jul 10

18:43

OEIS Server: https://oeis.org/edit/global/37

#3 by N. J. A. Sloane at Thu Nov 11 07:34:06 EST 2010

LINKS

<a href="/Sindx_Ed.html#EKG">Index entries for sequences related to EKG sequence</a>

KEYWORD

nonn,new

nonn

#2 by N. J. A. Sloane at Fri Feb 27 03:00:00 EST 2009

LINKS

<a href="http://www.research.att.com/~njas/sequences/Sindx_Ed.html#EKG">Index entries for sequences related to EKG sequence</a>

KEYWORD

nonn,new

nonn

#1 by N. J. A. Sloane at Fri May 16 03:00:00 EDT 2003

NAME

Term at which n appears in A064413 (if it begins at 2).

DATA

0, 1, 4, 2, 9, 3, 13, 7, 5, 8, 19, 6, 27, 12, 10, 16, 32, 11, 36, 17, 14, 18, 42, 15, 23, 26, 21, 25, 56, 22, 60, 30, 20, 31, 24, 29, 66, 35, 28, 39, 73, 34, 80, 40, 38, 41, 88, 44, 49, 45, 33, 46, 99, 47, 52, 48, 37, 55, 106, 51, 114, 59, 50, 63, 53, 58, 127, 64, 43, 54, 133

OFFSET

1,3

COMMENTS

Every nonnegative number appears here exactly once.

LINKS

J. C. Lagarias, E. M. Rains and N. J. A. Sloane, <a href="http://arXiv.org/abs/math.NT/0204011">The EKG sequence</a>, Exper. Math. 11 (2002), 437-446.

<a href="http://www.research.att.com/~njas/sequences/Sindx_Ed.html#EKG">Index entries for sequences related to EKG sequence</a>

CROSSREFS

Cf. A064413. Equals A064664 - 1.

KEYWORD

nonn

AUTHOR

Jonathan Ayres (Jonathan.ayres(AT)btinternet.com), Sep 30 2001

EXTENSIONS

More terms from Naohiro Nomoto (n_nomoto(AT)yabumi.com), Sep 30 2001

STATUS

approved