OFFSET
1,1
COMMENTS
The subset p, 2p-1, 4p-3 is a Cunningham chain of the 2nd kind, cf. A057326.
LINKS
Wikipedia, Cunningham chain
FORMULA
a(n) = A237189(n) + 1.
MATHEMATICA
Select[Range[10^5], AllTrue[{#, 2# - 1, 3# - 2, 4# - 3}, PrimeQ] &] (* Amiram Eldar, Jul 07 2020 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Jeppe Stig Nielsen, Jul 07 2020
STATUS
approved