Create a boolean array " prime [ 0 . . high ] " and initialize all entries it as true . A value in prime [ i ] will finally be false if i is Not a prime , else true .
let prime = new Array ( high + 1 ) ; let twin = false ; for ( let i = 0 ; i < high + 1 ; i ++ ) prime [ i ] = true ; prime [ 0 ] = prime [ 1 ] = false ;