Number of sequences which has HEAD at alternate positions to the right of the first HEAD | function to calculate total sequences possible ; Value of N is even ; Value of N is odd ; Driver code
function findAllSequence ( N ) { if ( N % 2 == 0 ) { return ( Math . pow ( 2 , N / 2 + 1 ) + Math . pow ( 2 , N / 2 ) - 2 ) ; } else { return ( Math . pow ( 2 , ( N + 1 ) / 2 ) + Math . pow ( 2 , ( N + 1 ) / 2 ) - 2 ) ; } } let N = 2 ; document . write ( findAllSequence ( N ) ) ;