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 A152442 #13 Feb 19 2025 11:18:37
%S A152442 4,15,16,21,25,27,30,33,35,36,39,42,49,50,51,54,55,57,64,65,66,69,70,
%T A152442 75,77,78,81,85,87,91,93,95,98,100,102,105,110,111,114,115,119,120,
%U A152442 121,123,125,129,130,133,135,138,140,141,143,144,145,147,150,154,155,159,161
%N A152442 n is included if the largest divisor of n that is coprime to d(n) is a composite, where d(n) is the number of divisors of n.
%C A152442 A137926(a(n)) is composite for all n.
%H A152442 Harvey P. Dale, <a href="/A152442/b152442.txt">Table of n, a(n) for n = 1..1000</a>
%t A152442 a = {}; For[n = 2, n < 1000, n++, b = Max[Select[Divisors[n], GCD[DivisorSigma[0, n], # ] == 1 &]]; If[b > 1 && ! PrimeQ[b], AppendTo[a, n]]]; a (* _Stefan Steinerberger_, Dec 06 2008 *)
%t A152442 ldcQ[n_]:=CompositeQ[Max[Select[Divisors[n],CoprimeQ[#,DivisorSigma[0,n]]&]]]; Select[Range[200],ldcQ] (* _Harvey P. Dale_, Feb 19 2025 *)
%Y A152442 Cf. A137926, A152444.
%K A152442 nonn
%O A152442 1,1
%A A152442 _Leroy Quet_, Dec 04 2008
%E A152442 More terms from _Stefan Steinerberger_ and _Ray Chandler_, Dec 06 2008