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A141520 a(1) = 0, a(2) = a(3) = 1; a(n) = a(n-1)*a(n-2) + a(n-2)*a(n-3) for n > 3. 1
0, 1, 1, 1, 2, 3, 8, 30, 264, 8160, 2162160, 17645379840, 38152152118080000, 673209215875134265982054400, 25684380411361480419900838705211915059200000 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,5

REFERENCES

Martin Gardner, Mathematical Circus, Random House, New York, 1981, p. 165.

LINKS

Michael De Vlieger, Table of n, a(n) for n = 1..21

MATHEMATICA

t={0, 1, 1}; Do[AppendTo[t, t[[-3]]*t[[-2]]+t[[-2]]*t[[-1]]], {n, 13}]; t (* Vladimir Joseph Stephan Orlovsky, Feb 03 2012 *)

Nest[Append[#, #[[-1]] #[[-2]] + #[[-2]] #[[-3]]] &, {0, 1, 1}, 12] (* Michael De Vlieger, Dec 17 2017 *)

PROG

(MATLAB)

function y=fib(n)

%Generates running geometric numbers

fz(1)=0; fz(2)=1; fz(3)=1;

for k=4:n

fz(k)=fz(k-2)*(fz(k-1)+fz(k-3));

end

y=fz(n);

CROSSREFS

Sequence in context: A054104 A053556 A001048 * A072042 A160586 A162074

Adjacent sequences:  A141517 A141518 A141519 * A141521 A141522 A141523

KEYWORD

nonn

AUTHOR

Matt Wynne (matwyn(AT)verizon.net), Aug 11 2008

STATUS

approved

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Last modified February 19 09:34 EST 2018. Contains 299330 sequences. (Running on oeis4.)