%I #20 Feb 15 2020 23:22:15
%S 697,1241,1513,1649,1921,2329,2993,3281,3649,3961,3977,4097,4369,4633,
%T 4777,5321,5617,5729,6001,6497,6817,6953,7081,7361,7633,7769,7913,
%U 8249,8633,8857,9553,9673,9809,9881,10001,10057,10081,10217,10489,10537
%N Product of exactly two distinct primes congruent to 1 mod 8 (A007519).
%C Subset of semiprimes A001358. Subset of {d = p_1 * p_2 * ... * p_m where p_i == 1 (mod 8), 1 <= i <= m are distinct primes} as occurs in Wei, p. 2.
%H Vincenzo Librandi, <a href="/A185377/b185377.txt">Table of n, a(n) for n = 1..1000</a>
%H Dasheng Wei, <a href="http://arxiv.org/abs/1102.3811">On the equation x^2-Dy^2=n</a>, Feb 18, 2011.
%F {A007519(i) * A007519(j) for i < j}.
%F {A000040(i) * A000040(j) for i < j, and A000040(i) in A017077 and A000040(j) in A017077}.
%e 10001 is in this sequence because 10001 = 73 * 137 = A007519(3) * A007519(7).
%t p = Select[Prime[Range[200]], Mod[#, 8] == 1 &]; Sort[Reap[Do[n=p[[i]] p[[j]]; If[n <= p[[1]]p[[-1]], Sow[n]], {i, 2, Length[p]}, {j, i - 1}]][[2,1]]]
%o (PARI) list(lim)=my(v=List(),P=List(),t); forprime(p=2,lim\17, if(p%8==1, listput(P,p))); for(i=2,#P, my(p=P[i]); for(j=1,i-1, t=p*P[j]; if(t>lim, break); listput(v,t))); Set(v) \\ _Charles R Greathouse IV_, Jul 03 2016
%Y Cf. A000040, A001358, A007519, A017077.
%K nonn,easy
%O 1,1
%A _Jonathan Vos Post_, Feb 20 2011