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A056569
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Row sums of Fibonomial triangle A010048.
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7
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1, 2, 3, 6, 14, 42, 158, 756, 4594, 35532, 349428, 4370436, 69532964, 1407280392, 36228710348, 1186337370456, 49415178236344, 2618246576596392, 176462813970065208, 15128228719573952976, 1649746715671916095304
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OFFSET
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0,2
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LINKS
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FORMULA
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a(n) = Sum_{m=0..n} A010048(n, m), where A010048(n, m) = fibonomial(n, m).
a(n) ~ c * ((1+sqrt(5))/2)^(n^2/4), where
c = EllipticTheta[3,0,1/GoldenRatio] / QPochhammer[-1/GoldenRatio^2] = 2.082828701647012450835512317685120373906427048806222527375... if n is even,
c = EllipticTheta[2,0,1/GoldenRatio] / QPochhammer[-1/GoldenRatio^2] = 2.082828691334156222136965926255238646603356514964103252122... if n is odd.
Or c = Sum_{j} ((1+sqrt(5))/2)^(-(j+(1-(-1)^n)/4)^2) / A062073, where A062073 = 1.2267420107203532444176302... is the Fibonacci factorial constant.
(End)
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MATHEMATICA
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Table[Sum[Product[Fibonacci[j], {j, 1, n}] / Product[Fibonacci[j], {j, 1, k}] / Product[Fibonacci[j], {j, 1, n-k}], {k, 0, n}], {n, 0, 20}] (* Vaclav Kotesovec, Apr 30 2015 *)
(* Or, since version 10 *) Table[Sum[Fibonorial[n]/Fibonorial[k]/Fibonorial[n-k], {k, 0, n}], {n, 0, 20}] (* Vaclav Kotesovec, Apr 30 2015 *)
Round@Table[Sum[GoldenRatio^(k(n-k)) QBinomial[n, k, -1/GoldenRatio^2], {k, 0, n}], {n, 0, 20}] (* Round is equivalent to FullSimplify here, but is much faster - Vladimir Reshetnikov, Sep 25 2016 *)
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PROG
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(Maxima) ffib(n):=prod(fib(k), k, 1, n);
fibonomial(n, k):=ffib(n)/(ffib(k)*ffib(n-k));
makelist(sum(fibonomial(n, k), k, 0, n), n, 0, 30); \\ Emanuele Munarini, Apr 02 2012
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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