6+16+26+.....+n.c

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

    printf("The value of n: ");
    scanf("%d",&n);

    for(i=6;i<=n;i=i+10)
        sum=sum+i;

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

    return 0;
}


--------------------------------------------------------------------------------------------------

Output--

The value of n: 106

Summation is = 616