A166582 Primes containing the string 444.

4441, 4447, 14447, 14449, 24443, 44417, 44449, 44453, 44483, 44491, 44497, 54443, 54449, 74441, 74449, 84443, 84449, 94441, 94447, 124447, 134443, 144407, 144409, 144413, 144427, 144439, 144451, 144461, 144479, 144481, 144497, 164443, 164447

Offset: 1

Author

Vincenzo Librandi, Nov 01 2009

Keywords

• nonn
• base

Links

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

Crossrefs

Cf. A166571-A166573, A166579-A166581.

Programs

Mathematica

p444Q[n_] :=  Module[{idn = IntegerDigits[n]}, MemberQ[Partition[idn, 3, 1], {4, 4, 4}]]; Select[Prime[Range[20000]], p444Q] (* Vincenzo Librandi Sep 14 2012 *)
Select[Prime[Range[16000]],SequenceCount[IntegerDigits[#],{4,4,4}]>0&] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Mar 15 2018 *)

Formula

a(n) ~ n log n. - Charles R Greathouse IV, Nov 01 2022

Extensions

Corrected (144491 replaced by 144497) by R. J. Mathar, Nov 30 2009