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Pseudoprimes (base-2) equal to product of 4 primes not necessarily distinct.
1

%I #7 Nov 10 2019 13:44:12

%S 11305,18705,23001,39865,41041,55245,62745,63973,72885,75361,101101,

%T 107185,126217,129921,157641,172081,188461,212421,215265,266305,

%U 272251,278545,332949,340561,367081,401401,449065,451905,464185,493885,552721,622909,656601,658801

%N Pseudoprimes (base-2) equal to product of 4 primes not necessarily distinct.

%H Amiram Eldar, <a href="/A112441/b112441.txt">Table of n, a(n) for n = 1..10000</a>

%e a(1) = 11305 = 5*7*17*19.

%t Select[Range[700000], PrimeOmega[#] == 4 && PowerMod[2, # - 1, #] == 1 &] (* _Amiram Eldar_, Nov 10 2019 *)

%Y Intersection of A014613 and A001567.

%K easy,nonn

%O 1,1

%A _Shyam Sunder Gupta_, Dec 11 2005

%E More terms from _Amiram Eldar_, Nov 10 2019