number series 0, 0, 2, 1, 4, 2, 6, 3, 8, 4, 10, 5, 12, 6, 14, 7, 16, 8
#include<stdio.h>
int main()
{
int i, n, a=0, b=0;
printf("enter number : ");
scanf("%d",&n);
for(i=1;i<=n;i++)
{
if(i%2!=0)
{
if(i>1)
a = a + 2;
}
else
{
b = a/2;
}
}
if(n%2!=0)
{
printf("%d",a);
}
else
{
printf("%d",b);
}
return 0;
}