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A166573 Prime numbers containing the string 13. 16
13, 113, 131, 137, 139, 313, 613, 1013, 1213, 1301, 1303, 1307, 1319, 1321, 1327, 1361, 1367, 1373, 1381, 1399, 1613, 1913, 2113, 2131, 2137, 2213, 2713, 3137, 3313, 3413, 3613, 4013, 4133, 4139, 4513, 4813, 5113, 5413, 5813, 6113, 6131, 6133, 7013, 7213, 8513 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
Eric Weisstein's World of Mathematics, Triskaidekaphobia
FORMULA
a(n) ~ n log n. - Charles R Greathouse IV, Nov 09 2011
MATHEMATICA
p13Q[n_] := Module[{idn = IntegerDigits[n]}, MemberQ[Partition[idn, 2, 1], {1, 3}]]; Select[Prime[Range[1000]], p13Q] (* Vincenzo Librandi, Sep 14 2012 *)
Select[Prime[Range[1500]], ! StringFreeQ[ToString[#], "13"] &] (* Vincenzo Librandi, May 03 2015 *)
PROG
(Haskell)
import Data.List (isInfixOf)
a166573 n = a166573_list !! (n-1)
a166573_list = filter (("13" `isInfixOf`) . show) a000040_list
-- Reinhard Zumkeller, Nov 09 2011
(PARI) contains(n, k)=my(N=digits(n), K=digits(k)); for(i=0, #N-#K, for(j=1, #K, if(N[i+j]!=K[j], next(2))); return(1)); 0
is(n)=isprime(n) && contains(n, 13) \\ Charles R Greathouse IV, Jun 20 2014
CROSSREFS
Complement of A076805 with respect to A000040.
Sequence in context: A302307 A293873 A044345 * A044726 A303038 A141937
KEYWORD
nonn,base
AUTHOR
Vincenzo Librandi, Nov 01 2009
EXTENSIONS
Corrected (313 inserted) by R. J. Mathar, Nov 30 2009
STATUS
approved

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Last modified July 15 21:13 EDT 2024. Contains 374334 sequences. (Running on oeis4.)