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

Author

N. J. A. Sloane, Oct 30 2001

Keywords

• nonn

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

Crossrefs

Cf. A064413, A064472 for better version.

Programs

Haskell

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

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 *)