C, Getting errors in symbolic constant definitions (possibly in function parameters)

I have been getting this error in a C program that I'm writing:

progra10.c:48:25: error: expected ‘;’, ‘,’ or ‘)’ before numeric constant
#define LAST_INDEX ARRAY_SIZE - 1

and

program10.c:47:25: error: expected ‘;’, ‘,’ or ‘)’ before numeric constant
 #define ARRAY_SIZE       20
                         ^
program10.c:48:25: note: in expansion of macro ‘DATA_SIZE’
 #define LAST_INDEX      ARRAY_SIZE - 1
                         ^~~~~~~~~~
program10.c:64:42: note: in expansion of macro ‘LAST_INDEX’
 int  sequential_search(int seq_data, int LAST_INDEX, int search_target,

I use the GCC compiler with this command:

gcc -Wall -ansi -oprogram10.exe program10.c -lm

This is the code that the error seems to be referring to:

#define COURSE_NUMBER "C Programming" /* Class */
#define PROGRAM_NUMBER 10 /* Program Number */
#define PROGRAMMER_NAME "Name" /* Programmer's Name */
#define ARRAY_SIZE 20 /* Size of the array */
#define LAST_INDEX ARRAY_SIZE - 1 /* The last index in the array */

I have no clue why it would be causing that error. I've checked for open comments, tabs, open strings, among other things, and I have not been able to fix this error. While compiling, this error is the only error, only it repeats for every time that LAST_INDEX is used in a function call parameter in main. I know the rest of my program has errors, but the compilation doesn't even show them, leading me to believe that it can't get past this.

The functions look like this:

Function Prototype:

int  sequential_search(int seq_data, int LAST_INDEX, int search_target, 
                                                   int target_location);

Function Call:

sequential_search(seq_data, LAST_INDEX, search_target, target_location);

Function Definition:

int sequential_search(int seq_data, int LAST_INDEX, int search_target,
                                                    int target_location)

Thanks for your help!