Sylvester's sequence: Difference between revisions
m
→{{header|Python}}
JsfasdF256 (talk | contribs) No edit summary |
|||
Line 900:
reduce(lambda a, x: a + 1 / x, xs, 0)
)
# MAIN ---
if __name__ == '__main__':
main()</lang>
{{Out}}
<pre>First 10 terms of OEIS A000058:
2
3
7
43
1807
3263443
10650056950807
113423713055421844361000443
12864938683278671740537145998360961546653259485195807
165506647324519964198468195444439180017513152706377497841851388766535868639572406808911988131737645185443
Sum of the reciprocals of the first 10 terms:
0.9999999999999999</pre>
Or as an iteration:
<lang python>'''Sylvester's sequence'''
from functools import reduce
from itertools import islice
# sylvester :: [Int]
def sylvester():
'''A non finite sequence of the terms of OEIS A000058
'''
return iterate(
lambda x: x * (x - 1) + 1
)(2)
# ------------------------- TEST -------------------------
# main :: IO ()
def main():
'''First terms, and sum of reciprocals.'''
print("First 10 terms of OEIS A000058:")
xs = list(islice(sylvester(), 10))
print('\n'.join([
str(x) for x in xs
]))
print("\nSum of the reciprocals of the first 10 terms:")
print(
reduce(lambda a, x: a + 1 / x, xs, 0)
)
# ----------------------- GENERIC ------------------------
# iterate :: (a -> a) -> a -> Gen [a]
def iterate(f):
'''An infinite list of repeated
applications of f to x.
'''
def go(x):
v = x
while True:
yield v
v = f(v)
return go
| |||