%I A138766
%S A138766 1,2,4,7,11,14,8,31,167,558,1572,4025,9645,21922,47536,98431,193935,
%T A138766 360094,617100,929593,1056037,145682,4258520,18546401,58207561,
%U A138766 158790322,398072524,938582407,2103831971,4502207934
%V A138766 1,2,4,7,11,14,8,-31,-167,-558,-1572,-4025,-9645,-21922,-47536,-98431,
               -193935,-360094,
%W A138766 -617100,-929593,-1056037,-145682,4258520,18546401,58207561,158790322,
               398072524,
%X A138766 938582407,2103831971,4502207934
%N A138766 Real part of upper left and lower right terms of [1,(1+I); 1,1]^n * [1,
               0].
%C A138766 The sequence exhibits curious strings of (-) signs.
%F A138766 Real part of terms (1,1) and (2,2) of matrix [1,(1+I); 1,1]^n * [1,0]; 
               I^2 = -1.
%e A138766 a(5) = 11 since fifth power of the matrix generator = [(11,20),(3,27); 
               (15,12),(11,20)]; where (11,20) = (11 + 20*I).
%Y A138766 Sequence in context: A165288 A086795 A064690 this_sequence A054850 A167805 
               A027427
%Y A138766 Adjacent sequences: A138763 A138764 A138765 this_sequence A138767 A138768 
               A138769
%K A138766 sign
%O A138766 1,2
%A A138766 Gary W. Adamson (qntmpkt(AT)yahoo.com), Mar 30 2008