This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A139589 #19 Oct 16 2019 01:28:10 %S A139589 1,1,2,3,5,13,89,233,610,987,1597,10946,28657,514229,3524578,9227465, %T A139589 24157817,39088169,63245986,433494437,1836311903,2971215073, %U A139589 7778742049,20365011074,591286729879,4052739537881,17167680177565,44945570212853 %N A139589 Fibonacci numbers with Fibonacci number of divisors. %C A139589 A000005(a(n)) is a Fibonacci number. %C A139589 For the terms shown here (in the Data section) the number of divisors is 1 or 2 or 8. - _Emeric Deutsch_, May 12 2008 %C A139589 Up to n = 104 the number of divisors is still 1, 2 or 8. - _Amiram Eldar_, Oct 15 2019 %H A139589 Amiram Eldar, <a href="/A139589/b139589.txt">Table of n, a(n) for n = 1..104</a> %p A139589 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 %p A139589 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 %t A139589 With[{s = Array[Fibonacci, 80]}, Select[s, ! FreeQ[s, DivisorSigma[0, #]] &]] (* _Michael De Vlieger_, Oct 15 2019 *) %Y A139589 Cf. A000005, A000045, A063375, A133021. %K A139589 nonn %O A139589 1,3 %A A139589 _Omar E. Pol_, May 09 2008 %E A139589 More terms from _R. J. Mathar_ and _Emeric Deutsch_, May 11 2008