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A038772
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Numbers not divisible by any of their digits.
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31
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23, 27, 29, 34, 37, 38, 43, 46, 47, 49, 53, 54, 56, 57, 58, 59, 67, 68, 69, 73, 74, 76, 78, 79, 83, 86, 87, 89, 94, 97, 98, 203, 207, 209, 223, 227, 229, 233, 239, 247, 249, 253, 257, 259, 263, 267, 269, 277, 283, 289, 293, 299, 307, 308, 323, 329, 334, 337, 338
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listen;
history;
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internal format)
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OFFSET
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1,1
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COMMENTS
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This is a regular language when written in decimal, though the minimal regular expression is probably thousands of characters long. - Charles R Greathouse IV, Aug 19 2011
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LINKS
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EXAMPLE
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34 is divisible by neither 3 nor 4.
35 is excluded because 5 is a divisor of 35, but 37 is included because neither 3 nor 7 is a divisor of 37
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MATHEMATICA
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nddQ[n_]:=Module[{idn=DeleteCases[IntegerDigits[n], 0]}, And@@Table[ !Divisible[n, idn[[i]]], {i, Length[idn]}]]; Select[Range[350], nddQ] (* Harvey P. Dale, Nov 01 2011 *)
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PROG
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(Haskell)
import Data.Char (digitToInt)
a038772 n = a038772_list !! (n-1)
a038772_list = filter p [1..] where
p n = all (> 0) $ map ((mod n) . digitToInt) $ filter (> '0') $ show n
(PARI) is(n)=my(v=vecsort(eval(Vec(Str(n))), , 8)); for(i=if(v[1], 1, 2), #v, if(n%v[i]==0, return(0))); 1 \\ Charles R Greathouse IV, Jul 22 2011
(Magma) [k:k in [1..340]| forall{c:c in Set(Intseq(k)) diff {0}|k mod c ne 0}]; // Marius A. Burtea, Dec 22 2019
(Python)
def ok(n): return not any(n%int(d) == 0 for d in str(n) if d != '0')
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CROSSREFS
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KEYWORD
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base,easy,nonn,nice
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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