

A064421


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


13



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
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OFFSET

1,3


COMMENTS

Every nonnegative number appears here exactly once.


LINKS

Table of n, a(n) for n=1..71.
J. C. Lagarias, E. M. Rains and N. J. A. Sloane, The EKG sequence, Exper. Math. 11 (2002), 437446.
Index entries for sequences related to EKG sequence


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] (* JeanFrançois Alcover, Aug 30 2018, after Robert G. Wilson v *)


CROSSREFS

Cf. A064413. Equals A064664  1.
Sequence in context: A060734 A075594 A076022 * A051494 A262025 A118013
Adjacent sequences: A064418 A064419 A064420 * A064422 A064423 A064424


KEYWORD

nonn


AUTHOR

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


EXTENSIONS

More terms from Naohiro Nomoto, Sep 30 2001


STATUS

approved



