text: Program to find the N | PHP program to find n - th number containing only 3 and 5. ; If n is odd , append 3 and move to parent ; If n is even , append 5 and move to parent ; Reverse res and return . ; Driver code
code: < ? php function findNthNo ( $ n ) { $ res = " " ; while ( $ n >= 1 ) { if ( $ n & 1 ) { $ res = $ res + "3" ; $ n = ( $ n - 1 ) / 2 ; } else { $ res = $ res . "5" ; $ n = ( $ n - 2 ) / 2 ; } } $ res = strrev ( $ res ) ; return $ res ; } $ n = 5 ; echo findNthNo ( $ n ) ; ? >