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 A176069 #15 Jan 25 2024 04:51:47
%S A176069 21,57,91,111,133,183,381,553,703,813,871,993,1057,1191,1261,1333,
%T A176069 1561,1641,1807,1893,1981,2071,2257,2353,2653,2757,2863,3193,3661,
%U A176069 4033,4291,4971,5257,5403,5853,6807,6973,7141,7311,7483,8373,8557,8743,9121,9313,9507,9703
%N A176069 Numbers of the form k^2+k+1 that are the product of two distinct primes.
%H A176069 David A. Corneth, <a href="/A176069/b176069.txt">Table of n, a(n) for n = 1..10000</a>
%e A176069 21 is a term as 21 = 3*7 = 4^2+4+1; 21 is the product of two distinct primes and 21 is of the form k^2 + k + 1.
%t A176069 f[n_]:=Last/@FactorInteger[n]=={1,1};Select[Array[ #^2+#+1&,6!,2],f[ # ]&]
%Y A176069 Cf. A002061, A006881, A174969.
%K A176069 nonn
%O A176069 1,1
%A A176069 _Vladimir Joseph Stephan Orlovsky_, Apr 07 2010
%E A176069 Name corrected by _David A. Corneth_, May 29 2023