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A227289 Smallest m such that gcd(A227113(m+1), A227113(m)) = n. 2

%I

%S 1,2,4,10,6,177,8,514,500,349,14,4791,16,5949,1623,863,20,2629,22,

%T 5113,2043,3211,28,7347,4593,11911,1647,12819,34,27325,36,15755,34527,

%U 29319,5459,2797,42,24535,20145,15511,46,26523,48,64895,13335,40769,54,43835,184041

%N Smallest m such that gcd(A227113(m+1), A227113(m)) = n.

%C A227288(a(n)) = n and A227288(m) <> n for m < a(n).

%e . n | a(n) | A227288(a(n)) = gcd(A227113(a(n)),A227113(a(n)+1))

%e . ---+--------+--------------- -----------------------------------

%e . 1 | 1 | 1 = gcd(1,2)

%e . 2 | 2 | 2 = gcd(2,4)

%e . 3 | 4 | 3 = gcd(3,6)

%e . 4 | 10 | 4 = gcd(8,12)

%e . 5 | 6 | 5 = gcd(5,10)

%e . 6 | 177 | 6 = gcd(168,162)

%e . 7 | 8 | 7 = gcd(7,14)

%e . 8 | 514 | 8 = gcd(472,480)

%e . 9 | 500 | 9 = gcd(459,468)

%e . 10 | 349 | 10 = gcd(330,320)

%e . 11 | 14 | 11 = gcd(11,22)

%e . 12 | 4791 | 12 = gcd(4524,4512)

%o (Haskell)

%o import Data.List (elemIndex); import Data.Maybe (fromJust)

%o a227289 = (+ 1) . fromJust . (`elemIndex` a227288_list)

%K nonn

%O 1,2

%A _Reinhard Zumkeller_, Jul 05 2013

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Last modified October 25 01:40 EDT 2021. Contains 348233 sequences. (Running on oeis4.)