public static void main(String[] args) {   int max = 10;   for (int len = 1; len <= max; len++) {    System.out.println(getNarc(len, ""));   }  }  static StringBuffer strb = new StringBuffer();  static String getNarc(int len, String start) {   for (int basenum = 1; basenum <= 9; basenum++) {    if (len == 2 || len == 1) {     StringBuffer tmpbuf = new StringBuffer();     tmpbuf.append(start);     for (int j = 0; j < len; j++) {      tmpbuf.append(basenum);     }     tmpbuf.append(new StringBuffer(start).reverse().toString());     strb.append(tmpbuf);     strb.append("\n");     // System.out.println(tmpbuf);    } else if (len > 2) {     String nextStr = "";     if (null != start) {      nextStr = start + basenum;     } else {      nextStr = Integer.toString(basenum);     }     getNarc(len - 2, nextStr);    }   }   return strb.toString();  }