A296117 - OEIS

%I #21 Dec 07 2017 02:03:28

%S 161038,49699666,760569694,4338249646,357647681422,547551530002,

%T 3299605275646,22999986587854,42820164121582,55173914702146,

%U 69345154539266,353190859033982

%N Base-2 pseudoprimes of the form 2*p*q where p and q are primes.

%C a(5) and a(10) are found by McDaniel (1989).

%C Terms in this sequence are of the form 2pq where p and q are distinct odd primes (A075819). - _Charles R Greathouse IV_, Dec 05 2017

%H W. L. McDaniel, <a href="https://doi.org/10.1090/S0025-5718-1989-0968152-6">Some pseudoprimes and related numbers having special forms</a>, Math. Comp. 53:187 (1989), 407-409.

%o (PARI) list(lim)=my(v=List(),pq); forprime(p=3,lim\6, forprime(q=3,min(lim\(2*p),p), pq=p*q; if(Mod(4,pq)^pq==2, listput(v,2*pq)))); Set(v) \\ _Charles R Greathouse IV_, Dec 05 2017

%Y Subsequence of A006935 and hence of A015919.

%Y The even terms of A215672.

%Y Intersection of A006935 and A215672. - _Felix Fröhlich_, Dec 05 2017

%Y Cf. A270973, A075819, A001220.

%K nonn,more

%O 1,1

%A _Max Alekseyev_, Dec 05 2017