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 A081304 #3 Mar 30 2012 18:50:31 %S A081304 1,2,3,4,5,6,7,8,9,9,10,11,12,12,13,14,15,16,17,17,17,17,18,19,20,20, %T A081304 21,21,22,22,23,24,24,24,25,26,27,27,27,27,28,28,29,29,30,30,31,32,33, %U A081304 33,33,33,34,35,35,35,35,35,36,36,37,37,37,38,38,38,39,39,39,39,40,41,42 %N A081304 Number of numbers m <= n with prime factors less than 2*spf(m), where spf(m) is the smallest prime factor of m (A020639). %C A081304 a(n)+A081305(n)=n; a(114)=A081305(114)=57; %C A081304 a(n)>=n/2 for n<=114, a(n)<n/2 for n>114. %Y A081304 Cf. A081306, A081303. %K A081304 nonn %O A081304 1,2 %A A081304 _Reinhard Zumkeller_, Mar 17 2003