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A195993 Numbers n such that 90n + 73 is prime.

%I A195993 #26 May 02 2017 18:59:13
%S A195993 0,1,4,5,6,9,11,12,15,18,19,20,22,23,27,28,29,32,36,39,40,42,43,49,51,
%T A195993 54,55,56,61,62,63,65,70,72,74,75,85,88,91,92,93,95,96,97,98,103,104,
%U A195993 106,109,110,113,114,116,127,128,131
%N A195993 Numbers n such that 90n + 73 is prime.
%C A195993 This sequence results from the propagation (addition) of 12 Fibonacci-like sequences; this sequence contains (recovers) all digital root 1 and last digit 3 prime numbers.
%H A195993 Ivan Neretin, <a href="/A195993/b195993.txt">Table of n, a(n) for n = 1..10000</a>
%F A195993 a(n) = (A142326(n)-73)/90.
%p A195993 A142326 := proc(n)
%p A195993         option remember;
%p A195993         if n = 1 then
%p A195993                 73 ;
%p A195993         else
%p A195993                 a := nextprime(procname(n-1)) ;
%p A195993                 while (a mod 45) <> 28 do
%p A195993                         a := nextprime(a) ;
%p A195993                 end do;
%p A195993                 return a;
%p A195993         end if;
%p A195993 end proc:
%p A195993 A195993 := proc(n)
%p A195993         (A142326(n)-73)/90 ;
%p A195993 end proc:
%p A195993 seq(A195993(n),n=1..80) ; # _R. J. Mathar_, Oct 31 2011
%t A195993 Select[Range[0,200],PrimeQ[90#+73]&] (* _Harvey P. Dale_, May 05 2014 *)
%o A195993 (PARI) is(n)=isprime(90*n+73) \\ _Charles R Greathouse IV_, Apr 25 2016
%Y A195993 Cf. A181732, A198382.
%K A195993 nonn,easy
%O A195993 1,3
%A A195993 _J. W. Helkenberg_, Oct 27 2011