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A123741
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A second version of Fibonacci factorials besides A003266.
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4
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1, 2, 24, 630, 52800, 11381760, 6738443712, 10487895163200, 43294107630090240, 469590163875486482400, 13388418681612808458240000, 1001088091286168023193223168000, 196239953628635168336022309340569600
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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COMMENTS
| The formula below is a generalization of n! = product((n+1)-j,j=1..n) with numbers k replaced by Fibonacci numbers F(k+1):=A000045(k+1), k>=1.
These numbers come up in Vandermonde determinants involving Fibonacci numbers [F(2),...,F(n+1)]. See A123742.
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FORMULA
| a(n)= product(F(n+2)-F(j+1),j=1..n), n>=1.
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EXAMPLE
| n=3: (5-1)*(5-2)*(5-3)=4*3*2=24; n=4: (8-1)*(8-2)*(8-3)*(8-5)=7*6*5*3=630.
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CROSSREFS
| Cf. A003266(n+1):= product(F(j+1), j=1..n), n>=1, the usual Fibonacci factorials.
Sequence in context: A009251 A009447 A193442 * A012216 A012118 A012375
Adjacent sequences: A123738 A123739 A123740 * A123742 A123743 A123744
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KEYWORD
| nonn,easy
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AUTHOR
| Wolfdieter Lang (wolfdieter.lang(AT)physik.uni-karlsruhe.de) Oct 13 2006
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