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%I #12 Apr 29 2018 18:43:56
%S 18,21,30,32,39,71,72,78,84,86,89,93,95,98,107,108,135,143,150,152,
%T 159,161,165,170,173,177,179,180,192,198,203,221,243,245,248,261,269,
%U 281,282,294,302,306,315,320,329,336,338,347,369,374,378,395,399,423,425,443,446,449,456,458,471,500,504
%N Numbers n such that the string n10001 is prime.
%H Harvey P. Dale, <a href="/A105145/b105145.txt">Table of n, a(n) for n = 1..1000</a>
%e If n=18, then n10001 = 1810001 (prime).
%e If n=98, then n10001 = 9810001 (prime).
%p read("transforms") :
%p for n from 1 to 1000 do p := digcat2(n,10001) ; if isprime(p) then printf("%d,",n); end if; end do: # _R. J. Mathar_, Feb 02 2011
%t Select[Range[600],PrimeQ[#*10^5+10001]&] (* _Harvey P. Dale_, Apr 29 2018 *)
%Y Cf. A105106, A105107.
%K base,nonn,easy
%O 1,1
%A _Parthasarathy Nambi_, Apr 09 2005
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