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A160757 Averages of the Fibonacci numbers which take integer values. 1
1, 1, 5058, 262213938, 18124577012898, 187952389930860, 1409394295257361938, 116903055445824294157698, 10100618828005365858877129458, 81435914480042681825934186407384633298, 7505278652741640947693896415563573183203138, 700346071081054203480884565881868806176873272498 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,3
COMMENTS
The numbers n such that F(1)+F(2)+...+F(n)=F(n+2)-1 is divisible by n are given in A111035. [From Max Alekseyev, Jun 04 2009]
LINKS
FORMULA
1/n*Sum {j=1..n} Fibonacci_j is an integer.
a(n) = (A000045(A111035(n)+2)-1) / A111035(n) = A000071(A111035(n)+2) / A111035(n) [From Max Alekseyev, Jun 04 2009]
MATHEMATICA
lst = {}; Do[a = Sum[ Fibonacci@ j, {j, n}]/n; If[ IntegerQ@ a, AppendTo[lst, a]], {n, 250}]; lst
CROSSREFS
Cf. A050248, integer average of n primes for some n, A000045.
Sequence in context: A281679 A187356 A187354 * A046169 A209782 A058908
KEYWORD
easy,nonn
AUTHOR
Daniel Tisdale, May 25 2009
EXTENSIONS
Corrected and extended by Max Alekseyev and Robert G. Wilson v, Jun 04 2009
STATUS
approved

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Last modified June 23 20:17 EDT 2024. Contains 373653 sequences. (Running on oeis4.)