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A141522 a(1) = 0, a(2) = a(3) = 1; a(n) = a(n-1)*a(n-2) + a(n-1)*a(n-3) for n > 3. 1
0, 1, 1, 1, 2, 4, 12, 72, 1152, 96768, 118444032, 11598039613440, 1374840894208868352000, 15945621994910596019667697926144000, 21922693387137438627357958684974264478793362424463360000 (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

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

PROG

(MATLAB)

function y=fib(n)

%Generates running geometric numbers( second kind)

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

for k=4:n

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

end

y=fz(n);

(PARI) /* script that avoids arrays */

geom(n) = {

local(a=0, b=1, c=1, d);

print1(a", "b", "c", ");

for(x=1, n-3,

d=(a+b)*c;

print1(d", ");

a=b; b=c; c=d;

)

} \\ Cino Hilliard, Apr 29 2009

CROSSREFS

Sequence in context: A078919 A085864 A060935 * A114903 A038054 A003180

Adjacent sequences:  A141519 A141520 A141521 * A141523 A141524 A141525

KEYWORD

nonn

AUTHOR

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

STATUS

approved

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Last modified April 3 21:54 EDT 2020. Contains 333207 sequences. (Running on oeis4.)