def even_odd_1(n):
    summ = 1
    x = 1
    for i in range(1, n):
        if i%2 ==0:
            x = x + 5
        else:
            x = 2 * x
        summ = summ + x
    return summ/n

def even_odd_2(xmax):
    summ = 0
    n = 0
    x = 1
    while x < xmax:
        n = n + 1 
        summ = summ + x
        if n%2 ==0:
            x = x + 5
        else:
            x = 2 * x
    return summ/n

def sum_terms_1 (a, b, n):
    summ = a
    x = a
    for i in range(n-1):
        if x%b == 0 or x%10 == b:
            x = 2 * x
        else:
            x = 3 * x + b
        summ = summ + x
    return summ

def sum_terms_2 (a, b, xmax):
    summ = 0
    x = a
    while x < xmax:
        summ = summ + x
        if x%b == 0 or x%10 == b:
            x = 2 * x
        else:
            x = 3 * x + b
    return summ