This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A089581 #15 Jan 12 2022 14:01:50
%S A089581 6,35,143,323,667,1147,1763,2491,3599,4757,5767,7387,9797,11021,12317,
%T A089581 16637,19043,22499,25591,28891,32399,36863,39203,47053,51983,55687,
%U A089581 60491,67591,72899,77837,82919,95477,99221,111547,121103,126727,136891
%N A089581 a(n) = prime(2*n-1)*prime(2*n).
%C A089581 a(n+1) is the smallest squarefree composite number that is relatively prime to the first 2*n prime numbers.
%C A089581 Bisection of A006094. - _R. J. Mathar_, Jan 23 2013
%H A089581 Michael De Vlieger, <a href="/A089581/b089581.txt">Table of n, a(n) for n = 1..10000</a>
%F A089581 prime(2*n-1)*prime(2*n), n=1, 2, 3 ...
%e A089581 a(13)=9797
%t A089581 Table[Prime[2 n - 1] Prime[2 n], {n, 30}] (* _Michael De Vlieger_, Jul 21 2016 *)
%t A089581 Times@@@Partition[Prime[Range[80]],2] (* _Harvey P. Dale_, Jan 12 2022 *)
%o A089581 (PARI) p=2;q=3;i=1;a=vector(100);for(i=1,100,a[i]=p*q;p=nextprime(q+1);q=nextprime(p+1));a
%K A089581 easy,nonn
%O A089581 1,1
%A A089581 Norbert A'Campo (nac(AT)member.ams.org), Dec 29 2003
%E A089581 Edited by Zak Seidov, Jun 13 2006
%E A089581 Typo in PARI program fixed by _Zak Seidov_, May 19 2010