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a(0)=1; a(n) = a(n-1) * Fibonacci(3+n) * Fibonacci(1+n) / (Fibonacci(n))^2, n > 1.
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%I #15 Sep 08 2022 08:45:53

%S 1,3,30,180,1300,8736,60333,412335,2829310,19384200,132882696,

%T 910735488,6242420665,42785803515,293259265950,2010026277756,

%U 13776931957468,94428478367520,647222466507045,4436128656563175,30405678471399166

%N a(0)=1; a(n) = a(n-1) * Fibonacci(3+n) * Fibonacci(1+n) / (Fibonacci(n))^2, n > 1.

%C Similar recurrences a(n) = a(n-1)*F(a0+n-1)*F(b0+n-1)/( F(n)*F(c0+n-1)) are:

%C {a0,b0,c0} = {3,2,1) in A066258.

%C {a0,b0,c0} = {3,1,1) in A001654.

%C {a0,b0,c0} = {4,1,1) in A001655 and next for 5,6 as well.

%D Harry Hochstadt, The Functions of Mathematical Physics, Dover, New York, 1986, p. 93.

%H Vincenzo Librandi, <a href="/A177727/b177727.txt">Table of n, a(n) for n = 0..200</a>

%H <a href="/index/Rec">Index entries for linear recurrences with constant coefficients</a>, signature (5,15,-15,-5,1)

%F G.f.: ( -1+2*x ) / ( (x-1)*(x^2+3*x+1)*(x^2-7*x+1) ). - _R. J. Mathar_, Nov 17 2011

%F a(n) = A001656(n) - 2*A001656(n-1). - _R. J. Mathar_, Nov 17 2011

%p with (combinat):

%p A177727 := proc(n)

%p if n = 0 then

%p 1;

%p else

%p procname(n-1)*fibonacci(3+n)*fibonacci(1+n)/fibonacci(n)^2 ;

%p end if;

%p end proc:

%p seq(A177727(n),n=0..10) ; # _R. J. Mathar_, Nov 17 2011

%t a0 = 4; b0 = 2; c0 = 1;

%t a[0] = 1;

%t a[n_] := a[n] = (Fibonacci[(a0 + n - 1)]*Fibonacci[( b0 + n - 1)]/(Fibonacci[n]*Fibonacci[(c0 + n - 1)]))*a[n - 1];

%t Table[a[n], {n, 0, 30}]

%t LinearRecurrence[{5,15,-15,-5,1},{1,3,30,180,1300},30] (* _Vincenzo Librandi_, Nov 18 2011 *)

%o (Magma) I:=[1, 3, 30, 180, 1300]; [n le 5 select I[n] else 5*Self(n-1)+15*Self(n-2)-15*Self(n-3)-5*Self(n-4)+Self(n-5): n in [1..30]]; // _Vincenzo Librandi_, Nov 18 2011

%Y Cf. A066258, A001654, A001655, A001656, A001657.

%K nonn

%O 0,2

%A _Roger L. Bagula_, May 12 2010