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 A180422 #12 Oct 31 2013 17:56:06 %S A180422 2,3,7,11,19,31,53,83,139,229,373,607,983,1583,2579,4177,6763,10939, %T A180422 17707,28649,46351,75017,121379,196387,317797,514219,832003,1346249, %U A180422 2178283,3524569,5702867,9227443,14930341,24157811,39088157,63245971 %N A180422 Largest prime immediately preceding a Fibonacci number. %C A180422 Limit ratio of two consecutive elements of this sequence is phi=1.61803... the golden ratio. %H A180422 Harvey P. Dale, <a href="/A180422/b180422.txt">Table of n, a(n) for n = 4..1000</a> %e A180422 a(7)=53 that is the prime number preceding 55=fib(10). %e A180422 fib(1)=1, fib(2)=1 and fib(3)=2 are not accounted. %t A180422 NextPrime[#,-1]&/@Fibonacci[Range[4,40]] (* _Harvey P. Dale_, Oct 31 2013 *) %o A180422 (PARI) a(n)=precprime(fibonacci(n)-1) %Y A180422 Cf. A138184, A000045 %K A180422 nonn %O A180422 4,1 %A A180422 _Carmine Suriano_, Sep 03 2010 %E A180422 Program and cross-ref from _Charles R Greathouse IV_, Sep 08 2010