|
|
A261390
|
|
2 * Sum_{n>=3} 1/Fibonacci(n).
|
|
0
|
|
|
2, 7, 1, 9, 7, 7, 1, 3, 3, 2, 4, 8, 6, 3, 5, 5, 1, 0, 6, 3, 4, 4, 0, 2, 2, 6, 0, 5, 8, 3, 7, 8, 5, 4, 3, 5, 9, 3, 7, 7, 8, 1, 0, 2, 6, 7, 4, 6, 3, 9, 3, 6, 9, 7, 2, 9, 9, 1, 1, 0, 7, 6, 3, 0, 6, 5, 0, 2, 6, 0, 6, 3, 7, 9, 9, 3, 3, 6, 6, 7, 6, 7, 2, 3, 0, 8, 3, 2, 4, 3, 2, 9, 1, 3, 5, 8, 0, 1, 7, 4, 5, 9, 4, 0, 9
(list;
constant;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,1
|
|
COMMENTS
|
Also the decimal expansion of the sum of the reciprocals of averages of adjacent pairs of Fibonacci numbers: Sum_{n>=1} 2/(A000045(n) + A000045(n+1)).
|
|
LINKS
|
|
|
FORMULA
|
|
|
EXAMPLE
|
2.719771332486355106344022605837854359377810267463936972991107630650260637993...
|
|
MATHEMATICA
|
adjFibAvRecipSum = Table[Sum[2/(Fibonacci[n] + Fibonacci[n + 1]), {n, 1000}]]; N[adjFibAvRecipSum, 20]
s = 0; k = 1; a = 2; b = 3; While[k < 525, s = N[s + 1/a, 128]; k++; {a, b} = {b, a + b}]; RealDigits[ 2s, 10, 111][[1]] (* Robert G. Wilson v, Aug 21 2015 *)
|
|
PROG
|
|
|
CROSSREFS
|
|
|
KEYWORD
|
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|