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Smallest number m such that gcd(m,EKG(m)) = n, where EKG = A064413, the EKG sequence.
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%I #7 Aug 01 2019 03:48:47

%S 1,2,6,52,10,12,14,8,63,110,165,396,689,126,225,144,34,270,38,120,273,

%T 1430,828,2088,1475,1014,432,476,58,4290,62,576,495,612,5180,2448,

%U 4477,684,468,40,697,4158,3139,6028,810,8602,8601,4752,2499,850,867,5148

%N Smallest number m such that gcd(m,EKG(m)) = n, where EKG = A064413, the EKG sequence.

%C A247379(a(n)) = n and A247379(m) != n for m < a(n).

%H Reinhard Zumkeller, <a href="/A247383/b247383.txt">Table of n, a(n) for n = 1..206</a>

%o (Haskell)

%o import Data.IntMap (empty, member, (!), insert)

%o a247383 n = a247383_list !! (n-1)

%o a247383_list = f 1 1 empty where

%o f x z m | member x m = m ! x : f (x + 1) (x + 1) m

%o | member y m = f x (z + 1) m

%o | otherwise = f x (z + 1) (insert y z m)

%o where y = a247379 z

%Y Cf. A064413, A247379.

%K nonn

%O 1,2

%A _Reinhard Zumkeller_, Sep 16 2014