1+2+4+7+11......up to numbers

1+2+4+7+11......up to numbers

 

//1+2+4+7+11......up to numbers

#include<stdio.h>

main()

{

    int i,sum=1,n,sum1=0;

    printf("enter number");

    scanf("%d",&n);

    for(i=0;i<n;i++)

    {

        sum=sum+i;

        sum1=sum1+sum;

    }

    printf("result=%d",sum1);

}