%I A054485
%S A054485 1,7,27,101,377,1407,5251,19597,73137,272951,1018667,3801717,14188201,
%T A054485 52951087,197616147,737513501,2752437857,10272237927,38336513851,
%U A054485 143073817477,533958756057
%N A054485 A second order recursive sequence.
%D A054485 I. Adler, Three Diophantine equations - Part II, Fib. Quart., 7 (1969), 
               pps. 181-193.
%D A054485 A. H. Beiler, Recreations in the Theory of Numbers, Dover, N.Y., 1964, 
               pps. 122-125, 194-196.
%D A054485 E. I. Emerson, Recurrent Sequences in the Equation DQ^2=R^2+N, Fib. Quart., 
               7 (1969), pps. 231-242.
%H A054485 <a href="Sindx_Rea.html#recLCC">Index entries for sequences related to 
               linear recurrences with constant coefficients</a>
%H A054485 Tanya Khovanova, <a href="http://www.tanyakhovanova.com/RecursiveSequences/
               RecursiveSequences.html">Recursive Sequences</a>
%F A054485 a(n)=4a(n-1)-a(n-2), a(0)=1, a(0)=7.
%F A054485 G.f.: (1+3*x)/(1-4*x+x^2). [From Philippe DELEHAM (kolotoko(AT)wanadoo.fr), 
               Nov 03 2008]
%e A054485 a(n)={7*([2+sqrt(3)]^n-[2-sqrt(3)]^n)-([2+sqrt(3)]^(n-1)-[2-sqrt(3)]^(n-1))}/
               2*sqrt(3).
%Y A054485 Cf. A054491.
%Y A054485 Sequence in context: A059769 A135914 A006350 this_sequence A090856 A055917 
               A056120
%Y A054485 Adjacent sequences: A054482 A054483 A054484 this_sequence A054486 A054487 
               A054488
%K A054485 easy,nonn
%O A054485 0,2
%A A054485 Barry E. Williams, May 06 2000