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 A080363 #13 Sep 22 2019 08:03:57
%S A080363 6,10,12,14,15,20,21,22,24,26,28,30,33,34,35,38,39,40,42,44,45,46,48,
%T A080363 51,52,55,56,57,58,60,62,63,65,66,68,69,70,74,76,77,78,80,82,84,85,86,
%U A080363 87,88,90,91,92,93,94,95,96,99,102,104,105,106,110,111,112,114,115,116,117
%N A080363 Nonprime numbers k such that the largest prime divisor of k is unitary.
%H A080363 Amiram Eldar, <a href="/A080363/b080363.txt">Table of n, a(n) for n = 1..10000</a>
%e A080363 k=20 is not a prime; 20 = 2*2*5, largest prime factor is 5 and gcd(5, 20/5) = 1 so 5 is a unitary prime divisor of 20, so 20 is in the sequence.
%t A080363 ma[x_] := Part[Reverse[Flatten[FactorInteger[x]]], 2] k=0; Do[s=ma[n]; If[Equal[GCD[s, n/s], 1]&&!PrimeQ[n], Print[n]], {n, 2, 256}]
%Y A080363 Cf. A006530, A034444, A056169.
%K A080363 nonn
%O A080363 1,1
%A A080363 _Labos Elemer_, Feb 21 2003