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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
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: A015887 A158134 A184853 * A172004 A051508 A281230
KEYWORD
nonn
AUTHOR
Michel Lagneau, Mar 15 2010
STATUS
approved

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Last modified March 29 07:27 EDT 2024. Contains 371265 sequences. (Running on oeis4.)