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A256751 Index of A166133(n) in the list of divisors of A166133(n-1)^2 - 1.

%I A256751 #5 Apr 09 2015 16:28:24
%S A256751 2,4,3,5,2,7,2,8,3,7,4,6,4,10,8,4,12,2,11,3,10,6,11,4,8,6,12,10,4,12,
%T A256751 4,12,8,7,4,14,2,19,5,21,3,17,7,9,7,13,4,19,7,13,5,17,5,21,9,11,5,17,
%U A256751 3,17,7,9,13,17,5,17,6,12,5,24,4,16,12,8,6,15,2
%N A256751 Index of A166133(n) in the list of divisors of A166133(n-1)^2 - 1.
%C A256751 A166133(n) = A027750(A166133(n-1)^2-1,a(n)).
%H A256751 Reinhard Zumkeller, <a href="/A256751/b256751.txt">Table of n, a(n) for n = 4..10000</a>
%e A256751 n = 12: A166133(12) = 9, A166133(12-1) = 10, 10^2 - 1 = 99,
%e A256751 9 is the third term of divisors(99) = [1,3,9,11,33,99],
%e A256751 therefore a(12) = 3;
%e A256751 n = 13: A166133(13) = 16, A166133(13-1) = 9, 9^2 - 1 = 80,
%e A256751 16 is the seventh term of divisors(80) = [1,2,4,5,8,10,16,20,40,80],
%e A256751 therefore a(13) = 7.
%o A256751 (Haskell)
%o A256751 import Data.List (elemIndex); import Data.Maybe (fromJust)
%o A256751 a256751 n = (+ 1) $ fromJust $
%o A256751             a166133 n `elemIndex` a027750_row' (a166133 (n - 1) ^ 2 - 1)
%Y A256751 Cf. A166133, A027750.
%K A256751 nonn
%O A256751 4,1
%A A256751 _Reinhard Zumkeller_, Apr 09 2015