A214730 - OEIS

%I #18 Feb 01 2019 02:51:32

%S 3,3,3,3,13,19,43,3,61,13,29,11,5,53,73,53,23,17,229,13,3,3,17,149,5,

%T 239,5,13,223,71,3,11,31,73,97,43,11,83,149,277,311,383,127,11,3,31,

%U 233,61,61,13,73,107,613,137,53,367,467,53,233,277,17,53,109,449,151,97,13,281,103,233,193,23,7

%N Smallest prime q such that 9^n + q*3^n - 1 is prime.

%H Pierre CAMI, <a href="/A214730/b214730.txt">Table of n, a(n) for n = 1..4000</a>

%o (PFGW and SCRIPTIFY)

%o SCRIPT

%o DIM nn,0

%o DIM qq

%o DIMS tt

%o OPENFILEOUT myfile,a(n).txt

%o LABEL loopn

%o SET nn,nn+1

%o IF nn>4000 THEN END

%o SET qq,1

%o LABEL loopq

%o SET qq,qq+1

%o SETS tt,%d,%d\,;nn;p(qq)

%o PRP (3^nn+p(qq))*3^nn-1,tt

%o IF ISPRP THEN GOTO a

%o IF ISPRIME THEN GOTO a

%o GOTO loopk

%o LABEL a

%o WRITE myfile,tt

%o GOTO loopn

%Y Cf. A214700.

%K nonn

%O 1,1

%A _Pierre CAMI_, Jul 27 2012