OS01.java

public class s5535512037h1{
    public static void main(String args[]){
        int i, uInp = 0;
        if(args.length==1){

            try{
                uInp = Integer.parseInt(args[0]);
            }
            catch(NumberFormatException nfe){
                System.out.println(nfe.getMessage() + "\n The first argument must be an integer.");
                System.exit(1);
            }

            int[] sn = new int[uInp];
            for(i=0; i<uInp; i++)
            {
                if(i == 0 || i == 1)
                    sn[i]=1;
                else if(i == 2)
                    sn[i]=2;
                else if(i == 3)
                    sn[i]=3;
                else if((i%3) == 0)
                    sn[i]=sn[i-1];
                else
                    sn[i]=(sn[i-2]*2)-1;
                System.out.print(sn[i] + "  ");
            }

        }else{
            System.out.println("\n This program requires least one argument.");
        }
    }
    public static int findSn(int n, boolean dep){
        if(n<1) return 1;

        if(dep)System.out.print(findSn((n-1), true) + "\t");

        switch(n){
            case 0: case 1: return 1;
            case 2: return 2;
            case 3: return 3;
            default:
                if(n%3==0)
                    return (findSn((n-1), false));
                else
                    return (findSn((n-2), false)*2)-1;
        }

    }
}