%I #24 Feb 23 2024 07:28:28
%S 1,3,3,6,9,15,24,39,63,102,165,267,432,699,1131,1830,2961,4791,7752,
%T 12543,20295,32838,53133,85971,139104,225075,364179,589254,953433,
%U 1542687,2496120,4038807,6534927,10573734,17108661,27682395,44791056,72473451,117264507
%N a(0) = 1; for n>0, a(n) = 3*Fibonacci(n).
%C Binomial transform is A097136.
%H <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (1,1).
%F G.f. : (1+2*x-x^2)/(1-x-x^2).
%F a(n) = a(n-1)+a(n-2) for n>2.
%F a(2n) = A097134(n); a(2n+1) = 3*F(2n+1).
%t Join[{1}, Table[3*Fibonacci[n], {n, 70}]] (* _Vladimir Joseph Stephan Orlovsky_, Feb 10 2012 *)
%o (PARI) a(n)=if(n,3*finonacci(n),1) \\ _Charles R Greathouse IV_, Oct 16 2015
%Y Cf. A000032, A000045.
%Y Essentially the same as A022086.
%K nonn,easy
%O 0,2
%A _Paul Barry_, Jul 26 2004
%E Definition rewritten by _N. J. A. Sloane_, Jan 24 2010