A064425 Gaps between where primes occur in A064413.

3, 5, 4, 6, 8, 5, 4, 6, 14, 4, 6, 7, 7, 8, 11, 7, 8, 13, 6, 4, 13, 9, 7, 15, 7, 8, 6, 4, 9, 20, 17, 6, 5, 15, 8, 10, 8, 9, 14, 8, 8, 19, 8, 6, 4, 20, 19, 10, 8, 6, 14, 4, 12, 13, 14, 9, 7, 13, 10, 9, 8, 24, 6, 12, 7, 23, 10, 16, 9, 6, 11, 18, 8, 17, 6, 6, 20, 10, 15

Offset: 1

Author

N. J. A. Sloane, Oct 01 2001

Keywords

• nonn

Links

• T. D. Noe, Table of n, a(n) for n=1..1000
• J. C. Lagarias, E. M. Rains and N. J. A. Sloane, The EKG sequence, arXiv:math/0204011 [math.NT], 2002.
• J. C. Lagarias, E. M. Rains and N. J. A. Sloane, The EKG sequence, Exper. Math. 11 (2002), 437-446.
• Index entries for sequences related to EKG sequence

Crossrefs

Cf. A064413. First differences of A064955 and also of A064423.

Cf. A137847.

Programs

Mathematica

terms = 80;
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}, 12 terms];
fp[n_] := FirstPosition[EKG, Prime[n]][[1]];
Array[fp, terms] // Differences (* Jean-François Alcover, Sep 02 2018, after Robert G. Wilson v in A064413 *)