def f( x ) a = 1 (1..x).each { |i| a = a * i } return a end def comb( n , r ) return f( n ) / ( f( r ) * f( n-r ) ) end x = 10 (1..x).each { |j| (1..j).each { |i| printf( "%dC%d=%d " , j , i , comb( j , i ) ) } printf( "\n" ) }