%I A018837
%S A018837 0,3,2,3,2,3,4,5,4,5,6,7,6,7,8,9,8,9,10,11,10,11,12,13,12,13,
%T A018837 14,15,14,15,16,17,16,17,18,19,18,19,20,21,20,21,22,23,22,23,
%U A018837 24,25,24,25,26,27,26,27
%N A018837 Number of steps for knight to reach (n,0) on infinite chess-board.
%F A018837 2[ (n+2)/4 ] if n even, 2[ (n+1)/4 ]+1 if n odd (n >= 8).
%F A018837 G.f.: x(3-x+x^2-x^3-2x^4+2x^5)/((1-x)^2*(1+x)(1+x^2)). a(n)=A083219(n), 
               n<>1. [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Dec 15 2008]
%Y A018837 Sequence in context: A095206 A049071 A029211 this_sequence A097618 A039639 
               A023509
%Y A018837 Adjacent sequences: A018834 A018835 A018836 this_sequence A018838 A018839 
               A018840
%K A018837 nonn,easy
%O A018837 0,2
%A A018837 N. J. A. Sloane (njas(AT)research.att.com), Marc LeBrun (mlb(AT)well.com)