%I A077238
%S A077238 4,5,11,16,40,59,149,220,556,821,2075,3064,7744,11435,28901,42676,
%T A077238 107860,159269,402539,594400,1502296,2218331,5606645,8278924,20924284,
%U A077238 30897365,78090491,115310536,291437680
%N A077238 Combined Diophantine Chebyshev sequences A077236 and A077235.
%C A077238 a(n)^2 - 3*b(n)^2 = 13, with the companion sequence b(n)= A077237(n).
%H A077238 <a href="Sindx_Ch.html#Cheby">Index entries for sequences related to 
               Chebyshev polynomials.</a>
%F A077238 a(2*k)= A077236(k) and a(2*k+1)= A077235(k), k>=0.
%F A077238 G.f.: (1-x)*(4+9*x+4*x^2)/(1-4*x^2+x^4).
%e A077238 11 = a(2) = sqrt(3*A077237(2)^2 + 13) = sqrt(3*6^2 + 13)= sqrt(121) = 
               11.
%Y A077238 Sequence in context: A066898 A118143 A001350 this_sequence A000286 A036539 
               A000769
%Y A077238 Adjacent sequences: A077235 A077236 A077237 this_sequence A077239 A077240 
               A077241
%K A077238 nonn,easy
%O A077238 0,1
%A A077238 Wolfdieter Lang (wolfdieter.lang(AT)physik.uni-karlsruhe.de), Nov 08 
               2002