OFFSET
1,1
LINKS
Muniru A Asiru, Table of n, a(n) for n = 1..5000
FORMULA
a(n) = (A005384(n+1) + 1)/2. - Hilko Koning, Jul 19 2018
MAPLE
select(k->isprime(2*k-1) and isprime(4*k-1), [$1..1000]); # Muniru A Asiru, Jul 19 2018
MATHEMATICA
Select[Range[1000], And @@ PrimeQ /@ ({2, 4}*# - 1) &] (* Ray Chandler, Nov 21 2006 *)
PROG
(GAP) Filtered([1..1000], p->IsPrime(2*p-1) and IsPrime(4*p-1)); # Muniru A Asiru, Jul 19 2018
CROSSREFS
KEYWORD
nonn
AUTHOR
Artur Jasinski, Nov 04 2006
EXTENSIONS
Extended by Ray Chandler, Nov 21 2006
STATUS
approved