Euler zigzag numbers ( Alternating Permutation ) | Function to print first n zigzag numbers ; To store factorial and n 'th zig zag number ; Initialize factorial upto n ; Set first two zig zag numbers ; Print first two zig zag number ; Print the rest zig zag numbers ; Binomial ( n , k ) * a ( k ) * a ( n - k ) ; Store the value ; Print the number ; Driver code ; Function call
function ZigZag ( n ) { var fact = Array ( n + 1 ) . fill ( 0 ) ; var zig = Array ( n + 1 ) . fill ( 0 ) ; fact [ 0 ] = 1 ; for ( var i = 1 ; i <= n ; i ++ ) fact [ i ] = fact [ i - 1 ] * i ; zig [ 0 ] = 1 ; zig [ 1 ] = 1 ; document . write ( " " ) ; document . write ( zig [ 0 ] + " " + zig [ 1 ] + " " ) ; for ( var i = 2 ; i < n ; i ++ ) { var sum = 0 ; for ( var k = 0 ; k <= i - 1 ; k ++ ) { sum += parseInt ( fact [ i - 1 ] / ( fact [ i - 1 - k ] * fact [ k ] ) ) * zig [ k ] * zig [ i - 1 - k ] ; } zig [ i ] = parseInt ( sum / 2 ) ; document . write ( parseInt ( sum / 2 ) + " " ) ; } } var n = 10 ; ZigZag ( n ) ;