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A139589 Fibonacci numbers with Fibonacci number of divisors. 4
1, 1, 2, 3, 5, 13, 89, 233, 610, 987, 1597, 10946, 28657, 514229, 3524578, 9227465, 24157817, 39088169, 63245986, 433494437, 1836311903, 2971215073, 7778742049, 20365011074, 591286729879, 4052739537881, 17167680177565, 44945570212853 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

A000005(a(n)) is a Fibonacci number.

For the terms shown here the number of divisors is 1 or 2 or 8. - Emeric Deutsch, May 12 2008

LINKS

Table of n, a(n) for n=1..28.

MAPLE

A000045 := proc(n) option remember ; coeftayl( x/(1-x-x^2), x=0, n) ; end: isA000045 := proc(n) local a; for a from 0 do if A000045(a) > n then RETURN(false) ; elif A000045(a)=n then RETURN(true) ; fi ; od: end: A000005 := proc(n) numtheory[tau](n) ; end: isA139589 := proc(n) RETURN(isA000045(n) and isA000045(A000005(n))) ; end: for i from 1 to 130 do a000045 := A000045(i) ; if isA139589(a000045) then printf("%d, ", a000045) ; fi ; od: # R. J. Mathar, May 11 2008

with(combinat): with(numtheory): F:={seq(fibonacci(k), k=1..100)}: a:=proc(n) if member(tau(fibonacci(n)), F)=true then fibonacci(n) else end if end proc: seq(a(n), n=1..70); # Emeric Deutsch, May 12 2008

CROSSREFS

Cf. A000005, A000045, A063375, A133021.

Sequence in context: A265785 A001685 A074691 * A152114 A139095 A005478

Adjacent sequences:  A139586 A139587 A139588 * A139590 A139591 A139592

KEYWORD

nonn

AUTHOR

Omar E. Pol, May 09 2008

EXTENSIONS

More terms from R. J. Mathar and Emeric Deutsch, May 11 2008

STATUS

approved

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Last modified June 19 23:01 EDT 2019. Contains 324222 sequences. (Running on oeis4.)