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Sequence of pairs k>0 and j>1 with the smallest j and the smallest sum j+k such that (k*j^n+1)*k*j^n-1 is prime.
2

%I #11 Oct 22 2013 12:26:16

%S 1,2,1,2,1,2,1,2,2,2,1,2,5,2,1,4,2,2,1,2,3,3,1,3,2,3,4,2,2,2,1,2,3,3,

%T 1,3,1,5,2,5,5,4,4,2,2,2,1,2,2,2,1,2,2,4,1,5,5,6,6,3,2,3,2,5,4,2,2,2,

%U 1,2,2,5,6,4,5,2,4,3,13,2,4,5,5,2,10,4,3,14,3,11,8,4,2,4,1,7,6,3,2,3,2,2,1,2,2,3,2,2,1,2,6,4,3,8,3,4,2,3,1,11,9,6,4,7,13

%N Sequence of pairs k>0 and j>1 with the smallest j and the smallest sum j+k such that (k*j^n+1)*k*j^n-1 is prime.

%H Pierre CAMI, <a href="/A227903/b227903.txt">Table of n, a(n) for n = 1..4000</a>

%o PFGW & SCRIPTIFY

%o SCRIPT

%o DIM n,0

%o DIM j

%o DIM k

%o DIM ss

%o DIMS tt

%o OPENFILEOUT myf,a(n).txt

%o LABEL a

%o SET n,n+1

%o IF n>2000 THEN END

%o SET ss,2

%o LABEL b

%o SET ss,ss+1

%o SET j,1

%o LABEL c

%o SET j,j+1

%o SET k,ss-j

%o IF k<1 THEN GOTO b

%o SETS tt,%d,%d,%d\,;n;k;j

%o PRP (k*j^n+1)*k*j^n-1,tt

%o IF ISPRP THEN GOTO d

%o GOTO c

%o LABEL d

%o WRITE myf,tt

%o GOTO a

%Y Cf. A156051, A230259.

%K nonn

%O 1,2

%A _Pierre CAMI_, Oct 15 2013