%I A083969
%S A083969 4,18,33,42,43,57,73,76,78,87,91,93,97,102,112,114,120,141,151,177,186,
%T A083969 193,196,219,261,267,276,280,300,307,318,322,342,352,364,366,402,435,
%U A083969 438,445,457,462,468,484,511,580,582,633,646,651,679,706,745,774,783
%N A083969 Numbers n such that 2.n.3.n.5.n.7.n.11 is prime (dot means concatenation).
%C A083969 2.4.3.4.5.4.7.4.11 = 2434547411, which is prime. Hence 4 is in the sequence.
%t A083969 v={};Do[If[PrimeQ[FromDigits[Join[{2}, IntegerDigits[n], {3}, IntegerDigits[n], 
               {5}, IntegerDigits[n], {7}, IntegerDigits[n], {1, 1}]]], v=Append[v, 
               n]], {n, 1000}];v
%t A083969 Select[Range[660], PrimeQ[FromDigits[Join[{2}, IntegerDigits[ # ], {3}, 
               IntegerDigits[ # ], {5}, IntegerDigits[ # ], {7}, IntegerDigits[ 
               # ], {1, 1}]]] &] - Stefan Steinerberger (stefan.steinerberger(AT)gmail.com), 
               Jun 28 2007
%Y A083969 Cf. A083677, A032711, A092115, A092117.
%Y A083969 Sequence in context: A003474 A095823 A092116 this_sequence A110621 A124978 
               A031081
%Y A083969 Adjacent sequences: A083966 A083967 A083968 this_sequence A083970 A083971 
               A083972
%K A083969 base,easy,nonn
%O A083969 1,1
%A A083969 Farideh Firoozbakht (f.firoozbakht(AT)sci.ui.ac.ir), Jun 19 2003
%E A083969 Edited by Stefan Steinerberger (stefan.steinerberger(AT)gmail.com), Jun 
               28 2007
%E A083969 Edited by N. J. A. Sloane (njas(AT)research.att.com), Sep 18 2008 at 
               the suggestion of R. J. Mathar.