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A140971 Numbers n such that arithmetic mean of squares of the first n nonzero Fibonacci numbers is an integer. 2
1, 2, 3, 5, 7, 12, 13, 15, 17, 23, 24, 25, 36, 37, 43, 47, 48, 50, 53, 60, 67, 72, 73, 75, 83, 96, 97, 103, 107, 108, 110, 113, 120, 125, 127, 137, 144, 157, 163, 167, 168, 170, 173, 175, 180, 192, 193, 195, 197, 216, 223, 227, 233, 240, 257, 263, 277, 283, 288, 293 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Is the root mean square RMS(F(0),...,F(n-1)) an integer for some n ?

LINKS

Harvey P. Dale, Table of n, a(n) for n = 1..1000

FORMULA

Numbers n such that A001654(n)/n is an integer.

EXAMPLE

n=2 : (A000045(1)^2+A000045(2)^2)/2 = 1

MATHEMATICA

nn=300; With[{fib2=Fibonacci[Range[nn]]^2}, Flatten[Position[Table[ Mean[ Take[ fib2, n]], {n, nn}], _?IntegerQ]]] (* Harvey P. Dale, May 02 2013 *)

CROSSREFS

Cf. A000045, A001654, A101907.

Sequence in context: A028843 A028842 A260181 * A073689 A257560 A187774

Adjacent sequences:  A140968 A140969 A140970 * A140972 A140973 A140974

KEYWORD

easy,nonn

AUTHOR

Ctibor O. Zizka, Jul 27 2008

EXTENSIONS

Edited and extended by R. J. Mathar, Aug 05 2008

STATUS

approved

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Last modified June 5 09:06 EDT 2020. Contains 334829 sequences. (Running on oeis4.)