A071202 - OEIS

%I #4 Mar 30 2012 18:51:38

%S 1,1,1,1,1,1,1,2,2,1,1,2,2,2,1,1,3,5,5,3,1,1,3,7,5,7,3,1,1,4,7,14,14,

%T 7,4,1,1,4,12,19,14,19,12,4,1,1,5,15,30,42,42,30,15,5,1,1,5,15,30,66,

%U 42,66,30,15,5,1,1,6,22,55,99,132,132,99,55,22,6,1,1,6,26,67,143,202,132

%N Array read by antidiagonals giving number of paths up and left from (0,0) to (n,k) where x/y<n/k (except at start and finish).

%F Some identities: a(n, k)=a(k, n); a(n, m*n)=a(n, m*n-1); a(n, n)=A000108(n-1); if n and k are coprime then a(n, k)=A071201(n, k)

%K nonn,tabl

%O 1,8

%A _Henry Bottomley_, May 16 2002