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A342846
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Number of distinct odd numbers visible as proper substrings of n.
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4
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0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 2, 1, 2, 1, 2, 1, 2, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 1, 2, 1, 1, 1, 2, 1, 2, 1, 2, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 1, 2, 1, 2, 1, 1, 1, 2, 1, 2, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 1, 2, 1, 2, 1, 2, 1, 1, 1, 2, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 1, 2, 1, 2, 1, 2, 1, 2, 1, 1, 1, 1, 1, 2, 1, 2
(list;
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listen;
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internal format)
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OFFSET
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1,13
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COMMENTS
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Here substrings are contiguous.
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LINKS
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EXAMPLE
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a(10)=1 since we can see 1 as a proper substring of 10.
a(105)=2 since we can see 1, 5.
a(132)=3 because we can see 1, 3, 13.
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PROG
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(Haskell)
import Data.List (isInfixOf)
a045888 n = length $ filter (`isInfixOf` (show n)) $ map show [1, 3..n-1]
-- Reinhard Zumkeller, Jul 19 2011
(Python)
def a(n):
s, eset = str(n), set()
for i in range(len(s)):
for j in range(i+1, len(s)+1):
if s[j-1] in "13579" and j-i < len(s): # odd and proper substring
eset.add(int(s[i:j]))
return len(eset)
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CROSSREFS
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KEYWORD
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nonn,base,easy
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AUTHOR
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STATUS
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approved
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