OFFSET
1,1
COMMENTS
a(5) and a(10) are found by McDaniel (1989).
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
LINKS
W. L. McDaniel, Some pseudoprimes and related numbers having special forms, Math. Comp. 53:187 (1989), 407-409.
PROG
(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
CROSSREFS
The even terms of A215672.
KEYWORD
nonn,more
AUTHOR
Max Alekseyev, Dec 05 2017
STATUS
approved