0,2
-3*a(n)^2 + b(n)^2 = 13, with the companion sequence b(n)= A077238(n).
Index entries for sequences related to Chebyshev polynomials.
a(2*k)= A054491(k) and a(2*k+1)= A077234(k), k>=0.
G.f.: (1+x)*(1+x+x^2)/(1-4*x^2+x^4).
3*a(2)^2 + 13 = 3*36+13 = 121 = 11^2 = A077238(2)^2.
Sequence in context: A047161 A048083 A127931 * A056879 A006746 A205875
Adjacent sequences: A077234 A077235 A077236 * A077238 A077239 A077240
nonn,easy
Wolfdieter Lang (wolfdieter.lang(AT)physik.uni-karlsruhe.de), Nov 08 2002
