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A271421
Fibonorial(3*n)/(fibonorial(2*n+1)*fibonorial(n+1)), where fibonorial(n) = A003266(n).
0
1, 4, 119, 23496, 32149806, 300214157831, 19246160432331107, 8451529006578585976752, 25443734373070679510011112460, 524973397889459587964008354031908560, 74243674067972394056586805754940632245000310, 71965837912588688126721254257169744333502564695515911
OFFSET
1,2
REFERENCES
S. R. Finch, Mathematical Constants, Cambridge, 2003, Section 1.2.5.
LINKS
Simon Plouffe, Fibonacci factorials.
Eric Weisstein's World of Mathematics, Fibonorial, Fibonacci Factorial Constant.
FORMULA
a(n) ~ 5*phi^(2*n^2 - 3*n - 2)/C where phi = (1+sqrt(5))/2, and C = (-1/phi^2; -1/phi^2)_inf is the Fibonacci factorial constant whose decimal expansion is given in A062073.
MATHEMATICA
Table[Fibonorial[3 n]/(Fibonorial[2 n + 1] Fibonorial[n + 1]), {n, 1, 30}] (* The sequence itself *)
QPochhammer[-1/GoldenRatio^2] (* The Fibonacci factorial constant C in the asymptotic expansion *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
STATUS
approved