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 A029827 #14 Mar 06 2020 03:18:30
%S A029827 15,45,51,55,57,63,85,95,99,111,115,117,119,123,153,171,185,187,201,
%T A029827 205,207,209,213,215,219,221,225,231,235,237,245,247,249,253,255,323,
%U A029827 333,335,355,365,369,387,391,393,395,405,407,411,415,417,423,425,429
%N A029827 Composite connected numbers: composite numbers k such that g(k) < g(u) + g(v) holds for all relatively prime factorizations k=u*v, where g(x) = ceiling(log_2 x).
%C A029827 Prime powers are not connected since they have no relatively prime factorizations. - _Michel Marcus_, Feb 25 2014
%D A029827 E. Labos, Spike Generating Dynamical Systems and Networks, In Lect. Notes in Economics and Mathematical Systems, pp. 189-206. Springer Verlag 1985.
%e A029827 k = 46665 = 5*9*17*61 is not a connected number because k = 61*765, but 16 >= 6 + 10.
%o A029827 (PARI) g(n) = ceil(log(n)/log(2));
%o A029827 isok(n) = {if (isprime(n), return (0)); d = divisors(n); gn = g(n); bpf = 0; for (i=2, #d-1, di = d[i]; if (gcd(di, n/di)==1, bpf = 1; if (gn >= g(di)+g(n/di), return (0)););); return (bpf);} \\ _Michel Marcus_, Feb 25 2014
%Y A029827 Cf. A029837, A036381-A036390, A034444.
%K A029827 nonn
%O A029827 1,1
%A A029827 _Labos Elemer_
%E A029827 a(40) corrected by _Sean A. Irvine_, Mar 05 2020