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A334141 Numbers that are the product of distinct twin primes.

%I A334141 #14 Feb 16 2025 08:34:00
%S A334141 1,3,5,7,11,13,15,17,19,21,29,31,33,35,39,41,43,51,55,57,59,61,65,71,
%T A334141 73,77,85,87,91,93,95,101,103,105,107,109,119,123,129,133,137,139,143,
%U A334141 145,149,151,155,165,177,179,181,183,187,191,193,195,197,199
%N A334141 Numbers that are the product of distinct twin primes.
%H A334141 Robert Israel, <a href="/A334141/b334141.txt">Table of n, a(n) for n = 1..10000</a>
%H A334141 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/TwinPrimes.html">Twin Primes</a>
%p A334141 N:= 1000: # for terms <= N
%p A334141 P:= select(isprime, {seq(i,i=3..N+2,2)}):
%p A334141 TP:= P intersect map(`+`,P,2):
%p A334141 TP:= map(t -> (t-2,t), TP):
%p A334141 TP:= sort(convert(TP,list)):
%p A334141 S:= {1}:
%p A334141 for i from 1 to nops(TP) do
%p A334141   S0:= S;
%p A334141   S:= S union map(`*`, select(`<=`,S,N/TP[i]),TP[i]);
%p A334141 od:
%p A334141 sort(convert(S,list)); # _Robert Israel_, Oct 28 2020
%Y A334141 Subsequence of A005117.
%Y A334141 Cf. A001097, A037074, A048599, A074480, A073485.
%K A334141 nonn
%O A334141 1,2
%A A334141 _Ilya Gutkovskiy_, Apr 15 2020