%I A055271
%S A055271 1,7,34,163,781,3742,17929,85903,411586,1972027,9448549,45270718,
%T A055271 216905041,1039254487,4979367394,23857582483,114308545021,547685142622,
%U A055271 2624117168089,12572900697823,60240386321026,288629030907307
%N A055271 a(n)=5a(n-1)-a(n-2); a(0)=1, a(1)=7.
%D A055271 I. Adler, Three Diophantine equations - Part II, Fib. Quart., 7 (1969), 
               pps. 181-193.
%D A055271 A. H. Beiler, Recreations in the Theory of Numbers, Dover, N.Y., 1964, 
               pps. 122-125, 194-196.
%D A055271 E. I. Emerson, Recurrent Sequences in the Equation DQ^2=R^2+N, Fib. Quart., 
               7 (1969), pps. 231-242.
%H A055271 <a href="Sindx_Rea.html#recLCC">Index entries for sequences related to 
               linear recurrences with constant coefficients</a>
%H A055271 Tanya Khovanova, <a href="http://www.tanyakhovanova.com/RecursiveSequences/
               RecursiveSequences.html">Recursive Sequences</a>
%F A055271 a(n)={7*[((5+sqrt(21))/2)^n-((5-sqrt(21))/2)^n]-[((5+sqrt(21))/2)^(n-1)-((5-sqrt(21))/
               2)^(n-1)]}/sqrt(21)
%e A055271 G.f.=(1+2x)/(1-5x+x^2).
%Y A055271 Cf. A030221.
%Y A055271 Sequence in context: A099242 A032206 A124466 this_sequence A027209 A080048 
               A027233
%Y A055271 Adjacent sequences: A055268 A055269 A055270 this_sequence A055272 A055273 
               A055274
%K A055271 easy,nonn
%O A055271 0,2
%A A055271 Barry E. Williams, May 10 2000
%E A055271 More terms from James A. Sellers (sellersj(AT)math.psu.edu), May 22 2000