login
This site is supported by donations to The OEIS Foundation.

 

Logo

Thanks to everyone who made a donation during our annual appeal!
To see the list of donors, or make a donation, see the OEIS Foundation home page.

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A174280 Smallest k such that tau(Fibonacci(k))= tau(Fibonacci(n+k)). 1
1, 3, 4, 3, 9, 5, 4, 3, 4, 3, 8, 5, 4, 3, 19, 6, 9, 5, 4, 3, 10, 7, 8, 5, 4, 3, 14, 6, 33, 13, 10, 9, 8, 13, 6, 7, 18, 5, 4, 3, 21, 5, 4, 3, 8, 16, 6, 31, 10, 9, 8, 9, 6, 19, 6, 18, 14, 27, 14, 19, 10, 9, 8, 9, 6, 16, 6, 26, 10, 9, 8, 11, 6, 42, 14, 7, 20, 5, 4, 3 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

tau(n) is the number of divisors of n (A000005).

LINKS

Table of n, a(n) for n=1..80.

Eric W. Weisstein, MathWorld: Divisor Function

EXAMPLE

a(2)= 3 because tau(Fibonacci(3))= tau(2)= 2, tau(Fibonacci(3+2)=tau(5)= 2.

MAPLE

with(numtheory) ;

with(combinat) ;

A174280 := proc(n)

        for k from 1 do

                if tau(fibonacci(k)) = tau(fibonacci(n+k)) then

                        return k;

                end if;

        end do:

end proc:

seq(A174280(n), n=1..80) ; # R. J. Mathar, Jul 06 2012

MATHEMATICA

Table[k = 1; While[DivisorSigma[0, Fibonacci[k]] != DivisorSigma[0, Fibonacci[k + n]], k++]; k, {n, 100}] (* T. D. Noe, Mar 18 2013 *)

CROSSREFS

Cf. A063375.

Sequence in context: A077628 A158134 A184853 * A172004 A051508 A281230

Adjacent sequences:  A174277 A174278 A174279 * A174281 A174282 A174283

KEYWORD

nonn

AUTHOR

Michel Lagneau, Mar 15 2010

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified January 20 14:13 EST 2019. Contains 319333 sequences. (Running on oeis4.)