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%I #18 Sep 08 2022 08:46:01
%S 0,1,2,3,6,7,9,10,13,14,16,18,20,22,24,25,27,29,31,32,38,39,43,44,49,
%T 50,51,53,56,63,64,65,66,69,77,80,83,84,87,90,91,95,98,101,102,105,
%U 106,107,108,109,111,116,118,120,121,122,123,129,132,134,135,137
%N Numbers n such that 90*n + 47 is prime.
%C A reverse reading of A142313; all entries of A142313 have digital root 2 and last digit 7.
%H Vincenzo Librandi, <a href="/A201734/b201734.txt">Table of n, a(n) for n = 1..10000</a>
%F a(n) = (A142313(n)-47)/90.
%p for n from 0 to 240 do
%p p := 90*n+47 ;
%p if isprime(p) then
%p printf("%d,",n) ;
%p end if;
%p end do: # _R. J. Mathar_, Dec 05 2011
%t Select[Range[0,400],PrimeQ[90 #+47]&] (* _Vincenzo Librandi_, Dec 11 2011 *)
%o (Magma) [n: n in [0..200] | IsPrime(90*n+47)]; // _Vincenzo Librandi_, Dec 11 2011
%o (PARI) is(n)=isprime(90*n+47) \\ _Charles R Greathouse IV_, Feb 17 2017
%Y Cf. A181732, A198382, A195993, A196000, A196007.
%K nonn,easy,less
%O 1,3
%A _J. W. Helkenberg_, Dec 04 2011
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