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 A153385 #38 Oct 05 2024 10:57:01 %S A153385 0,0,0,0,1,3,8,51,1329,393790,5670112879,43416847208976911 %N A153385 Number of primes <= Fibonacci(Fibonacci(n)) = pi(A007570(n)). %H A153385 Harry J. Smith, <a href="http://harry-j-smith-memorial.com/download.html#XICalc"> XICalc - Extra Precision Integer Calculator</a> [broken link] %H A153385 Kim Walisch, <a href="https://github.com/kimwalisch/primecount">Fast C++ prime counting function implementation (primecount)</a>. %F A153385 a(n) = pi(Fibonacci(Fibonacci(n))) = A000720(A007570(n)). %F A153385 a(n) = A054782(A000045(n)). - _Amiram Eldar_, Sep 03 2024 %e A153385 a(7) = 51 because Fibonacci(7) = 13, Fibonacci(13) = 233 and there are 51 primes <= 233. %t A153385 PrimePi@# & /@ (Fibonacci@Fibonacci@# & /@ Range@10) (* _Robert G. Wilson v_, Feb 17 2009 *) %o A153385 (XiCalc) Pi(Fib(Fib(n))); %o A153385 (Magma) [0] cat [#PrimesUpTo(Fibonacci(Fibonacci(n))): n in [1..9]]; // _Vincenzo Librandi_, Aug 02 2015 %Y A153385 Cf. A000045, A000720, A007570, A054782. %K A153385 nonn,more,hard %O A153385 0,6 %A A153385 _Harry J. Smith_, Dec 25 2008 %E A153385 a(11) calculated using Kim Walisch's primecount and added by _Amiram Eldar_, Sep 03 2024