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 A091220 #12 Jun 10 2018 20:35:10 %S A091220 1,2,2,3,3,4,2,4,4,6,2,6,2,4,4,5,5,8,2,9,3,4,4,8,2,4,6,6,4,8,2,6,4,10, %T A091220 4,12,2,4,6,12,2,6,4,6,8,8,2,10,4,4,6,6,4,12,2,8,6,8,2,12,2,4,6,7,9,8, %U A091220 2,15,3,8,4,16,2,4,8,6,4,12,4,15,3,4,8,9,7,8,2,8,4,16,2,12,4,4,6,12,2 %N A091220 Number of divisors of the n-th GF(2)[X]-polynomial. %H A091220 A. Karttunen, <a href="/A091247/a091247.scm.txt">Scheme-program for computing this sequence.</a> %H A091220 <a href="/index/Ge#GF2X">Index entries for sequences operating on GF(2)[X]-polynomials</a> %o A091220 (PARI) a(n)=local(p,fm,k);while(n>0,p+=Mod(n,2)*x^k;n\=2;k++);fm=factor(p);prod(k=1,matsize(fm)[1],fm[k,2]+1) \\ _Franklin T. Adams-Watters_, Jun 22 2010 %Y A091220 a(n) = A000005(A091203(n)) = A000005(A091205(n)). Cf. A091257. %K A091220 nonn %O A091220 1,2 %A A091220 _Antti Karttunen_, Jan 03 2004