%I A081768
%S A081768 1,2,3,3,5,5,3,7,7,5,7,5,7,11,9,3,5,13,9,13,7,3,11,9,7,9,7,11,11,9,3,9,
%T A081768 23,13,19,9,3,7,11,7,11,9,9,9,7,7,5,19,13,23,15,7,17,13,9,7,5,5,7,11,11,
%U A081768 11,19,11,15,9,11,21,19,11,9,9,9,13,11,5,13,21,9,11,15,7,13,9,7,11,7,15
%N A081768 Number of k, 1<=k<=n, such that C(n,k) divides C(2n,2k).
%C A081768 Is a(n) odd for n>2 ? All odd numbers occur? Does equation a(x)=2m+1 
               have infinitely many solutions for any m>=1?
%Y A081768 Sequence in context: A158745 A103310 A046146 this_sequence A072923 A131922 
               A113730
%Y A081768 Adjacent sequences: A081765 A081766 A081767 this_sequence A081769 A081770 
               A081771
%K A081768 easy,nonn
%O A081768 1,2
%A A081768 Benoit Cloitre (benoit7848c(AT)orange.fr), Apr 09 2003