#!/usr/bin/env python from common import factorial SIDE = 20 # Central binomial coefficients (permutations of 0,1) # ((2n)! choose n!^2 ) v = factorial(2 * SIDE) // (factorial(SIDE)**2) print(v)
def signedPerm(n):
print (factorial(n) * 2**n)
plist = range(1,n+1)
_perm([], plist, n)
from common import factorial
n = 100
sum = 0
fact_n = factorial(n)
for digit in str(fact_n):
sum += int(digit)
print sum
from common import factorial target = 1000000 first_digit = 3 perms_first_digit = target - factorial(9) * (first_digit - 1)
def perm(n):
print factorial(n)
plist = range(1,n+1)
_perm([], plist)
#!/usr/bin/env python
from common import factorial, to_digits
from itertools import count
fs = list(factorial(n) for n in range(0, 10))
S = 0
for i in count(10):
if i > 100000:
break
s = sum(fs[d] for d in to_digits(i))
if s == i:
S += i
print(S)
def get_S(p):
S = 0
for k in xrange(1, 5+1):
S += factorial(p-k)
return S % p
from itertools import permutations from common import factorial SIZE = 20 num_routes = factorial(2 * SIZE) / (factorial(SIZE)**2) print num_routes