program:
#include<stdio.h>
int main( )
{
int Tn,a,n,d;
printf("Enter first term :");
scanf("%d",&a);
printf("Enter difference :");
scanf("%d",&d);
printf("Enter 'n' terms :");
scanf("%d",&n);
Tn = a + ((n-1) * d);
printf("nth term :%d",Tn);
return 0;
}
output: