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A256417 The EKG sequence (A064413) smoothed by replacing each prime p with 2p and each thrice-prime 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 (list; graph; refs; listen; history; text; internal format)
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), 437-446.

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 } (* Jean-Fran├žois 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

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Last modified October 22 21:19 EDT 2021. Contains 348180 sequences. (Running on oeis4.)