%I A077237
%S A077237 1,2,6,9,23,34,86,127,321,474,1198,1769,4471,6602,16686,24639,62273,
%T A077237 91954,232406,343177,867351,1280754,3236998,4779839,12080641,17838602,
%U A077237 45085566,66574569,168261623
%N A077237 Combined Diophantine Chebyshev sequences A054491 and A077234.
%C A077237 -3*a(n)^2 + b(n)^2 = 13, with the companion sequence b(n)= A077238(n).
%H A077237 <a href="Sindx_Ch.html#Cheby">Index entries for sequences related to 
               Chebyshev polynomials.</a>
%F A077237 a(2*k)= A054491(k) and a(2*k+1)= A077234(k), k>=0.
%F A077237 G.f.: (1+x)*(1+x+x^2)/(1-4*x^2+x^4).
%e A077237 3*a(2)^2 + 13 = 3*36+13 = 121 = 11^2 = A077238(2)^2.
%Y A077237 Sequence in context: A047161 A048083 A127931 this_sequence A056879 A006746 
               A121624
%Y A077237 Adjacent sequences: A077234 A077235 A077236 this_sequence A077238 A077239 
               A077240
%K A077237 nonn,easy
%O A077237 0,2
%A A077237 Wolfdieter Lang (wolfdieter.lang(AT)physik.uni-karlsruhe.de), Nov 08 
               2002