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 A091232 #7 Mar 31 2012 14:02:20 %S A091232 0,0,1,0,2,1,4,5,13,19,38,69,129,242,451,848,1629,3039,5858,11041, %T A091232 21209,40478,77659,148986,286948,551944,1064949,2056282,3975512, %U A091232 7694488,14907270,28908990,56119905,109022319,211980753 %N A091232 How many more primes than irreducible GF(2)[X] polynomials there are in range [2^n,2^(n+1)]. %H A091232 A. Karttunen, <a href="/A091247/a091247.scm.txt">Scheme-program for computing this sequence.</a> %H A091232 <a href="/index/Ge#GF2X">Index entries for sequences operating on GF(2)[X]-polynomials</a> %F A091232 a(0)=a(1)=0, a(n) = A036378(n+1)-A001037(n). %e A091232 There are 5 primes (17,19,23,29,31) in range [16,32], while there are only 3 irreducible GF(2)[X]-polynomials in the same range: (19,25,31), thus a(4)=2. %Y A091232 First differences of A091231. %K A091232 nonn %O A091232 0,5 %A A091232 _Antti Karttunen_, Jan 03 2004