%N Numbers n such that C(6n,n)/(5n+1) (A002295) is not divisible by 6.
%C Is a(n)/n^2 bounded? It seems that 0.2<a(n)/n^2<=1
%Y Cf. A000225 (C(2n, n)/(n+1) is not divisible by 2), A003462 (C(3n, n)/(2n+1) is not divisible by 3), A003463 (C(5n, n)/(4n+1) is not divisible by 5).
%A _Benoit Cloitre_, Jan 14 2003