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 A075738 #9 Apr 17 2018 18:06:42 %S A075738 1,1,2,5,13,55,89,233,377,610,1597,4181,10946,17711,28657,121393, %T A075738 514229,1346269,3524578,5702887,9227465,24157817,39088169,63245986, %U A075738 165580141,433494437,1836311903,2971215073,20365011074,53316291173 %N A075738 Squarefree Fibonacci numbers whose indices are also squarefree. %e A075738 Fib(10)=55 is there because both 10 and 55 are squarefree. %p A075738 with(combinat, fibonacci): fib_supM_dsk := proc(n); if (numtheory[issqrfree](n)='true') then if (numtheory[issqrfree](fibonacci(n))='true') then RETURN(fibonacci(n)); fi; fi; end: seq(fib_supM_dsk(i), i=1..100); %t A075738 Select[With[{nn=70},Thread[{Range[nn],Fibonacci[Range[nn]]}]], AllTrue[#, SquareFreeQ]&][[All,2]] (* The program uses the AllTrue function from Mathematica version 10 *) (* _Harvey P. Dale_, Apr 17 2018 *) %Y A075738 Cf. A000045, A005117, A061305, A075739. %K A075738 easy,nonn %O A075738 1,3 %A A075738 _Jani Melik_, Oct 07 2002 %E A075738 Edited by _Don Reble_, Nov 05 2005