A224610 - OEIS

%I #22 Apr 22 2013 12:08:03

%S 2,2,5,7,59,142,264,25,8,21,124,33,60,87,9,231,5,6,82,155,7,66,72,21,

%T 42,105,15,48,250,68,222,54,47,195,255,360,205,6,83,26,5,1,50,220,173,

%U 1,976,30,228,130,30,129,46,1106,65,62,15,109,24,41,922,15,132,89

%N Smallest j such that j*2*prime(n)^3-1 and j*2*prime(n)*q^2-1 are prime.

%H Pierre CAMI, <a href="/A224610/b224610.txt">Table of n, a(n) for n = 1..10000</a>

%t a[n_] := For[p = Prime[n]; j = 1, j < 10^6, j++, If[PrimeQ[q = j*2*p^3 - 1] && PrimeQ[j*p*2*q^2 - 1], Return[j]]]; Table[a[n], {n, 1, 75}] (* _Jean-François Alcover_, Apr 22 2013 *)

%o (PFGW & SCRIPTIFY)

%o SCRIPT

%o DIM n,1

%o DIM j

%o DIM q

%o DIMS t

%o OPENFILEOUT myf,a(n).txt

%o LABEL a

%o SET n,n+1

%o SET j,0

%o LABEL b

%o SET j,j+1

%o SET q,j*2*p(n)^3-1

%o SETS t,%d\,;p(n)

%o PRP q,t

%o IF ISPRP THEN GOTO c

%o GOTO b

%o LABEL c

%o SET q,j*2*p(n)*q^2-1

%o PRP q,t

%o IF ISPRP THEN GOTO d

%o GOTO b

%o LABEL d

%o WRITE myf,t

%o GOTO a

%Y Cf. A224490, A224609, A224611, A224612.

%K nonn

%O 1,1

%A _Pierre CAMI_, Apr 12 2013