A243531 Prime numbers containing the string 15.

151, 157, 1151, 1153, 1511, 1523, 1531, 1543, 1549, 1553, 1559, 1567, 1571, 1579, 1583, 1597, 2153, 4153, 4157, 4159, 5153, 6151, 7151, 7159, 9151, 9157, 10151, 10159, 11159, 11503, 11519, 11527, 11549, 11551, 11579, 11587, 11593, 11597, 12157, 13151, 13159

Offset: 1

Author

Vincenzo Librandi, Jun 06 2014

Keywords

• nonn
• base
• less

Links

• Vincenzo Librandi, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. similar sequences listed in A243529.

Programs

Mathematica

Select[Prime[Range[2000]], !StringFreeQ[ToString[#], "15" ] &]
Select[Prime[Range[2000]],SequenceCount[IntegerDigits[#],{1,5}]>0&] (* Harvey P. Dale, Sep 19 2023 *)

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,15) \\ Charles R Greathouse IV, Jun 20 2014

Formula

a(n) ~ n log n. - Charles R Greathouse IV, Jun 20 2014