Hi! Please help russian shoolboy
Where the error is?
I realized that '1'-s are in the field of the sequence.
1 2 4 7 11 16
int main()
{
    long a,j,i,n;
    cin>>n;
    for(int x=0; x<n; x++)
    {
        cin>>a;
        i=1;
        j=1;
        while (a>i)
        {
           i=i+j;
           j++;
        }
        if (a==i)
            cout<<1;
        else
            cout<<0;
     }
    return 0;
}

while (a>i)
        {
           i=i+j;
           j++;
        }