A196007 - OEIS

%I #21 May 02 2017 18:58:32

%S 0,1,2,3,4,10,12,15,16,17,21,22,23,24,25,26,29,32,36,37,39,42,45,49,

%T 50,51,54,58,59,60,61,64,67,68,71,72,73,75,77,78,79,80,84,86,89,91,92,

%U 94,101,105,106,108,112,113,114,115,117,120

%N Numbers n such that 90n + 83 is prime.

%H Ivan Neretin, <a href="/A196007/b196007.txt">Table of n, a(n) for n = 1..10000</a>

%F a(n) = (A142332(n)-83)/90.

%p A142332 := proc(n)

%p         option remember;

%p         if n = 1 then

%p                 83 ;

%p         else

%p                 a := nextprime(procname(n-1)) ;

%p                 while (a mod 45) <> 38 do

%p                         a := nextprime(a) ;

%p                 end do;

%p                 return a;

%p         end if;

%p end proc:

%p A196007 := proc(n)

%p         (A142332(n)-83)/90 ;

%p end proc:

%p seq(A196007(n),n=1..80) ; # _R. J. Mathar_, Oct 31 2011

%t Select[Range[0, 120], PrimeQ[90 # + 83] &] (* _Ivan Neretin_, May 02 2017 *)

%o (PARI) is(n)=isprime(90*n+83) \\ _Charles R Greathouse IV_, Jul 12 2016

%Y Cf. A196000, A198382, A181732, A195993. These are digital root and last digit preserving sequences.

%K nonn,easy

%O 1,3

%A _J. W. Helkenberg_, Oct 27 2011