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%I #11 Jul 08 2020 20:35:15
%S 331,1531,3061,4261,4951,6841,10831,15391,18121,23011,25411,26041,
%T 31771,33301,40111,41491,45061,49831,53881,59341,65851,70141,73771,
%U 78541,88741,95461,96931,109471,111721,112621,117721,131311,133201,134731,135301,150151,165901
%N Numbers p such that p, 2p-1, 3p-2, 4p-3 are primes.
%C The subset p, 2p-1, 4p-3 is a Cunningham chain of the 2nd kind, cf. A057326.
%H Wikipedia, <a href="http://en.wikipedia.org/wiki/Cunningham_chain">Cunningham chain</a>
%F a(n) = A237189(n) + 1.
%t Select[Range[10^5], AllTrue[{#, 2# - 1, 3# - 2, 4# - 3}, PrimeQ] &] (* _Amiram Eldar_, Jul 07 2020 *)
%Y Cf. A005382, A057326, A067257, A237189, A336060.
%K nonn,easy
%O 1,1
%A _Jeppe Stig Nielsen_, Jul 07 2020