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%I #6 Aug 01 2019 00:11:02
%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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