%I #10 Apr 19 2023 00:29:14
%S 1,33,609,10945,196417,3524577,63245985,1134903169,20365011073,
%T 365435296161,6557470319841,117669030460993,2111485077978049,
%U 37889062373143905,679891637638612257,12200160415121876737
%N Odd terms in A027941.
%H <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (19,-19,1).
%F a(n) = F(6n+3) - 1 where F(k) denotes the k-th Fibonacci number.
%F G.f.: (1+14x+x^2)/((1-x)(1-18x+x^2)).
%t a[n_] := Fibonacci[6n+3]-1
%o (PARI) a(n)=fibonacci(6*n+3)-1
%o (PARI) a(n)=if(n<0,0,subst(poltchebi(n)+poltchebi(n+1),x,9)/5-1)
%Y Cf. A027941, A000045.
%K nonn,easy
%O 0,2
%A _Benoit Cloitre_, Oct 25 2002