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%I #10 Feb 26 2013 04:08:37
%S 1,2,3,5,5,9,9,14,17,14,9,17,26,27,33,14,26,27,41,17,44,33,50,51,53,
%T 41,14,65,44,27,69,50,51,77,53,80,81,33,84,87,65,98,99,101,41,69,105,
%U 44,77,26,17,80,81,122,125,84,51,129,87,131,53,134,137,98,99,149,101,152,153
%N Greatest preceding term in Hofstadter sequence A005244 that is a divisor of A005244(n)+1; a(1) = 1.
%C a(n) = (A005244(n) + 1) / A005244(k) for some k.
%H Reinhard Zumkeller, <a href="/A139127/b139127.txt">Table of n, a(n) for n = 1..10000</a>
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/HofstadterSequences.html">Hofstadter Sequences</a>
%H <a href="/index/Ho#Hofstadter">Index entries for Hofstadter-type sequences</a>
%o (Haskell)
%o a139127 1 = 1
%o a139127 n = head [y | let z = a005244 n + 1,
%o y <- reverse $ takeWhile (<= z `div` a020639 z) a005244_list,
%o z `mod` y == 0]
%o -- _Reinhard Zumkeller_, Feb 26 2013
%Y Cf. A020639.
%K nonn
%O 1,2
%A _Reinhard Zumkeller_, Apr 09 2008
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