OFFSET
1,1
COMMENTS
Reduction of a function f(x) by a substitution q(x)->s(x) is introduced at A193010.
FORMULA
From Amiram Eldar, Jan 18 2022: (Start)
Equals Sum_{k>=0} 2^(2*k+1)*Fibonacci(2*k+1)/(2*k+1)!.
Equals 2*cosh(1)*sinh(sqrt(5))/sqrt(5). (End)
EXAMPLE
6.3830192266109834906946736316102032592390...
MATHEMATICA
f[x_] := Sinh[2 x]; r[n_] := Fibonacci[n];
c[n_] := SeriesCoefficient[Series[f[x], {x, 0, n}], n]
u1 = N[Sum[c[n]*r[n], {n, 0, 100}], 100]
RealDigits[u1, 10]
CROSSREFS
KEYWORD
nonn,cons
AUTHOR
Clark Kimberling, Jul 15 2011
STATUS
approved