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 A091231 #7 Mar 31 2012 14:02:20 %S A091231 0,0,0,1,1,3,4,8,13,26,45,83,152,281,523,974,1822,3451,6490,12348, %T A091231 23389,44598,85076,162735,311721,598669,1150613,2215562,4271844, %U A091231 8247356,15941844,30849114,59758104,115878009,224900328 %N A091231 How many more primes than irreducible GF(2)[X] polynomials there are in range [0,2^n]. %H A091231 A. Karttunen, <a href="/A091247/a091247.scm.txt">Scheme-program for computing this sequence.</a> %H A091231 <a href="/index/Ge#GF2X">Index entries for sequences operating on GF(2)[X]-polynomials</a> %F A091231 a(0)=a(1)=0, a(n) = A007053(n)-A062692(n-1). %e A091231 There are 11 primes (2,3,5,7,11,13,17,19,23,29,31) in range [0,32], while there are only 8 irreducible GF(2)[X]-polynomials in the same range: (2,3,7,11,13,19,25,31), thus a(5)=3. %Y A091231 Partial sums of A091232. %K A091231 nonn %O A091231 0,6 %A A091231 _Antti Karttunen_, Jan 03 2004