A064953 Where the even terms appear in A064413.

2, 3, 4, 7, 8, 9, 12, 13, 16, 17, 18, 19, 23, 26, 27, 30, 31, 32, 35, 36, 40, 41, 42, 45, 46, 47, 48, 49, 52, 55, 56, 59, 60, 63, 64, 65, 66, 70, 71, 72, 73, 77, 79, 80, 83, 86, 87, 88, 91, 92, 94, 95, 98, 99, 102, 103, 104, 105, 106, 110, 113, 114

Offset

1,1

Comments

Complement of A064957; A195376(a(n)) = 0. [Reinhard Zumkeller, Sep 17 2001]

Links

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

J. C. Lagarias, E. M. Rains and N. J. A. Sloane, The EKG sequence, arXiv:math/0204011 [math.NT]; Exper. Math. 11 (2002), 437-446.

Index entries for sequences related to EKG sequence

Mathematica

ekg[s_List] := Block[{m = s[[-1]], k = 3}, While[MemberQ[s, k] || GCD[m, k] == 1, k++]; Append[s, k]]; A064413 = Nest[ekg, {1, 2}, 200];
Position[A064413, _?EvenQ] // Flatten (* Jean-François Alcover, Aug 02 2018, after Robert G. Wilson v *)

Prog

(Haskell)
import Data.List (findIndices)
a064953 n = a064953_list !! (n-1)
a064953_list = map (+ 1) $ findIndices even a064413_list
-- Reinhard Zumkeller, Sep 17 2001

Crossrefs

Cf. A064413, A064472 for better version.

Sequence in context: A105941 A276876 A047202 * A097503 A030701 A305924

Adjacent sequences: A064950 A064951 A064952 * A064954 A064955 A064956

Keyword

nonn

Author

N. J. A. Sloane, Oct 30 2001

Status

approved