A071202 Array read by antidiagonals giving number of paths up and left from (0,0) to (n,k) where x/y

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, 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, 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

Offset: 1

Author

Henry Bottomley, May 16 2002

Keywords

• nonn
• tabl

Formula

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)