A092117 - OEIS

%I #15 Sep 24 2018 16:53:14

%S 10,43,51,55,58,60,136,171,204,213,214,222,270,288,309,334,339,364,

%T 366,376,414,423,460,477,492,501,502,507,513,519,565,585,586,597,621,

%U 649,726,729,787,852,861,870,903,906,915,933,946,981,988,1005,1038,1071

%N Numbers n such that the concatenation 2n3n5n7n11n13 is prime.

%C This concatenation is fp(6, n) as defined in A083677.

%H Harvey P. Dale, <a href="/A092117/b092117.txt">Table of n, a(n) for n = 1..1000</a>

%e 10 is in the sequence because 210310510710111013 is prime.

%t v={};Do[If[PrimeQ[FromDigits[Join[{2}, IntegerDigits[n], {3}, IntegerDigits[n], {5}, IntegerDigits[n], {7}, IntegerDigits[n], {1, 1}, IntegerDigits[n], {1, 3}]]], v=Append[v, n]], {n, 1400}];v

%t fp6Q[n_] := PrimeQ[ FromDigits[ Flatten[ IntegerDigits /@ Insert[{2, 3, 5, 7, 11, 13}, n, {{2}, {3}, {4}, {5}, {6}}]]]]; Select[ Range[1100], fp6Q[ # ] &] (* _Robert G. Wilson v_, Dec 11 2004 *)

%t Select[Range[1100],PrimeQ[FromDigits[Flatten[IntegerDigits/@Riffle[{2,3,5,7,11,13}, #]]]]&] (* _Harvey P. Dale_, Mar 21 2013 *)

%Y Cf. A032711, A083677, A083966, A083677, A092115, A083969.

%K nonn,base

%O 1,1

%A _Farideh Firoozbakht_, Jun 15 2003

%E Edited by _N. J. A. Sloane_ at the suggestion of _Andrew S. Plewe_, May 27 2007