A223935 Odd primes p(i) such that 6*p(i+j)^2-1 is also prime for j = 0..3.

48497, 48907, 493747, 578453, 1223777, 1249363, 1933363, 3304607, 5160217, 5765083, 6022087, 6205937, 7740127, 7757447, 7862843, 8173537, 8938627, 11989177, 13789033, 17649223, 18142693, 18829117, 20006813, 20601593, 23938867, 24448063, 24478043

Offset

1,1

Links

Pierre CAMI, Table of n, a(n) for n = 1..131

Example

p(4990)=48497 and 6*48497*48497-1=14111754053 is prime,
p(4991)=48523 and 6*48523*48523-1=14126889173 is prime,
p(4992)=48527 and 6*48527*48527-1=14129218373 is prime,
p(4993)=48533 and 6*48533*48533-1=14132712533 is prime,
so a(1)=p(4990)=48497

Mathematica

Reap[ For[ n=1; i=2, i < 5*10^6, i++, If[And @@ PrimeQ /@ Table[p[j] = Prime[i+j]; 6*p[j]^2-1, {j, 0, 3}], Print["i = ", i, " a(", n, ") = ", p[0]]; n++; Sow[ p[0] ] ] ] ][[2, 1]] (* Jean-François Alcover, Apr 09 2013 *)

Prog

PFGW and SCRIPTIFY
SCRIPT
DIM i, 4000
DIMS t
OPENFILEOUT myf, res.txt
LABEL loop1
SET i, i+1
IF i==9999997 THEN END
SETS t, %d, %d\,; i; p(i)
PRP 6*p(i)*p(i)-1, t
IF  ISPRP THEN GOTO a
GOTO loop1
LABEL a
SET i, i+1
SETS t, %d, %d\,; i; p(i)
PRP 6*p(i)*p(i)-1, t
IF  ISPRP THEN GOTO b
GOTO loop1
LABEL b
SET i, i+1
SETS t, %d, %d\,; i; p(i)
PRP 6*p(i)*p(i)-1, t
IF  ISPRP THEN GOTO c
GOTO loop1
LABEL c
SET i, i+1
SETS t, %d, %d\,; i; p(i)
PRP 6*p(i)*p(i)-1, t
IF  ISPRP THEN WRITE myf, t
GOTO loop1

Crossrefs

Sequence in context: A151876 A083627 A031650 * A278020 A237105 A234230

Adjacent sequences: A223932 A223933 A223934 * A223936 A223937 A223938

Keyword

nonn

Author

Pierre CAMI, Mar 29 2013

Status

approved