View Compilation Error

0_0_23795279_4663.c: In function 'main':
0_0_23795279_4663.c:6:36: error: expected ';' before ')' token
         printf ("%d\n\n",(n+1)*n/2));
                                    ^
0_0_23795279_4663.c:6:36: error: expected statement before ')' token