(1+3+5+7....+N) + (1+4+7+...+N)

#include<stdio.h>
int main()
{
    int i, N, anik = 0, rob = 0, sum = 0;

    printf("Enter Any Number : ");
    scanf("%d", &N);

    for(i=1; i<=N; i+=2)
    {
        anik = anik + i;
    }

    for(i=1; i<=N; i+=3)
    {
        rob  = rob + i;
    }

    sum = anik + rob;

    printf("\nSummation is : %d\n", sum);

    return 0;

}