%I A040399
%S A040399 20,2,40,2,40,2,40,2,40,2,40,2,40,2,40,2,40,2,40,2,40,2,40,2,40,
%T A040399 2,40,2,40,2,40,2,40,2,40,2,40,2,40,2,40,2,40,2,40,2,40,2,40,2,
%U A040399 40,2,40,2,40,2,40,2,40,2,40,2,40,2,40,2,40,2,40,2,40,2,40,2,40
%N A040399 Continued fraction for sqrt(420).
%H A040399 <a href="Sindx_Con.html#confC">Index entries for continued fractions 
               for constants</a>
%F A040399 a(n)=21+19*(-1)^n-20*[C(2*n,n) mod 2], with n>=0 [From Paolo P. Lava 
               (ppl(AT)spl.at), Apr 30 2009]
%p A040399 with(numtheory): Digits := 300: convert(evalf(sqrt(420)),confrac);
%Y A040399 Sequence in context: A037926 A040397 A040398 this_sequence A040390 A040391 
               A118295
%Y A040399 Adjacent sequences: A040396 A040397 A040398 this_sequence A040400 A040401 
               A040402
%K A040399 nonn,cofr,easy
%O A040399 0,1
%A A040399 N. J. A. Sloane (njas(AT)research.att.com).