OFFSET
1,1
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..1000
FORMULA
a(n) ~ n log n. - Charles R Greathouse IV, Jun 20 2014
MATHEMATICA
Select[Prime[Range[90000]], !StringFreeQ[ToString[#], "111"]&]
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, 111) \\ Charles R Greathouse IV, Jun 20 2014
CROSSREFS
KEYWORD
nonn,base,easy
AUTHOR
Vincenzo Librandi, Jun 06 2014
STATUS
approved