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A166572 Prime numbers containing the string 11. 5
11, 113, 211, 311, 811, 911, 1103, 1109, 1117, 1123, 1129, 1151, 1153, 1163, 1171, 1181, 1187, 1193, 1511, 1811, 2011, 2111, 2113, 2311, 2411, 2711, 3011, 3119, 3511, 3911, 4111, 4211, 5011, 5113, 5119, 5711, 6011, 6113, 6211, 6311, 6911, 7211, 7411 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
FORMULA
a(n) ~ n log n. - Charles R Greathouse IV, Jun 20 2014
MAPLE
isA166572 := proc(n) local dgs, wrks; if isprime(n) then dgs := convert(n, base, 10) ; wrks := false; for i from 1 to nops(dgs)-1 do if op(i, dgs) = 1 and op(i+1, dgs) = 1 then return true; end if; od: return false; else false; end if; end proc: for n from 1 to 8000 do if isA166572(n) then printf("%d, ", n) ; end if; od: # R. J. Mathar, Nov 30 2009
MATHEMATICA
p11Q[n_]: = Module[{idn = IntegerDigits[n]}, MemberQ[Partition[idn, 2, 1], {1, 1}]] Select[Prime[Range[1000]], p11Q] (* Vincenzo Librandi, Sep 14 2012 *)
Select[Prime[Range[1000]], SequenceCount[IntegerDigits[#], {1, 1}]>0&] (* Harvey P. Dale, Sep 24 2022 *)
PROG
(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, 11) \\ Charles R Greathouse IV, Jun 20 2014
CROSSREFS
Sequence in context: A175684 A090227 A050758 * A111463 A142483 A001268
KEYWORD
nonn,base
AUTHOR
Vincenzo Librandi, Nov 01 2009
STATUS
approved

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Last modified April 18 18:58 EDT 2024. Contains 371781 sequences. (Running on oeis4.)