

A256417


The EKG sequence (A064413) smoothed by replacing each prime p with 2p and each thriceprime 3p also with 2p.


5



1, 4, 4, 4, 6, 6, 12, 8, 10, 10, 10, 18, 14, 14, 14, 24, 16, 20, 22, 22, 22, 27, 30, 25, 35, 28, 26, 26, 26, 36, 32, 34, 34, 34, 42, 38, 38, 38, 45, 40, 44, 46, 46, 46, 48, 50, 52, 54, 56, 49, 63, 60, 55, 65, 70, 58, 58, 58, 66, 62, 62
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OFFSET

1,2


COMMENTS

This smoothing of A064413 is discussed in Lagarias et al. (2002).
a(n) = A256415(A064413(n)).  Reinhard Zumkeller, Apr 06 2015


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], 2002.
J. C. Lagarias, E. M. Rains and N. J. A. Sloane, The EKG Sequence, Exper. Math. 11 (2002), 437446.


MATHEMATICA

ekg[s_] := Block[{m = s[[1]], k = 3}, While[MemberQ[s, k]  GCD[m, k] == 1, k++]; Append[s, k]];
Nest[ekg, {1, 2}, 100] /. {n_ /; PrimeQ[n] > 2n, n_ /; PrimeQ[n/3] > 2n/3 } (* JeanFrançois Alcover, Aug 04 2018, after Robert G. Wilson v *)


PROG

(Haskell)
a256417 = a256415 . a064413  Reinhard Zumkeller, Apr 06 2015


CROSSREFS

Cf. A064413, A256415, A256416.
Sequence in context: A219760 A097918 A256416 * A229630 A141466 A171743
Adjacent sequences: A256414 A256415 A256416 * A256418 A256419 A256420


KEYWORD

nonn


AUTHOR

N. J. A. Sloane, Apr 05 2015


STATUS

approved



