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, Nov 01 2022
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 *)
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Vincenzo Librandi, Nov 01 2009
EXTENSIONS
Corrected (144491 replaced by 144497) by R. J. Mathar, Nov 30 2009
STATUS
approved