def triangle_num_factors(f):
""" Find the first triangle number with at least f factors.
"""
n = 1
i = 2
while n < 100000000:
n += i
if not n % 60:
if len(euler.all_factors(n)) > f:
return n
i += 1
# 4179871
import euler
N = 28123
ab = []
for n in xrange(12, N+1):
if sum(euler.all_factors(n)[:-1]) > n:
ab.append(n)
abab = [n for n in xrange(N+1)]
for a in ab:
for b in ab:
if a + b > N:
break
abab[a+b] = 0
print sum(abab)
# 31626
import euler
N = 10000
s = 0
for a in xrange(2,N):
b = sum(euler.all_factors(a)[:-1])
db = sum(euler.all_factors(b)[:-1])
if a != b and a == db:
s += a
print s
