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 A385858 #9 Jul 14 2025 23:02:48
%S A385858 1,35,77,95,119,125,143,187,209,221,247,259,299,319,323,377,391,403,
%T A385858 427,437,473,493,527,551,589,629,667,697,713,731,779,799,817,851,893,
%U A385858 899,943,989,1007,1073,1139,1147,1189,1199,1219,1247,1271,1313,1333,1343,1357,1363,1387,1397
%N A385858 Numbers m in A385402 which are not prime.
%C A385858 Since all the primes are in A385402, this sequence is more concise.
%t A385858 fQ[m_] := Sum[ GCD[m, Floor[m/k]], {k, m}] == Sum[ GCD[m, Ceiling[m/k]], {k, m}]; j = 1; lst = {}; While[j < 1400, If[ !PrimeQ@ j && fQ@ j, AppendTo[lst, j]]; j++]; lst
%o A385858 (PARI) isok(m) = if (!isprime(m), sum(k=1, m, gcd(m, floor(m/k))) == sum(k=1, m, gcd(m, ceil(m/k)))); \\ _Michel Marcus_, Jul 10 2025
%Y A385858 Cf. A018804, A384628, A385398.
%Y A385858 Proper subset of A385402.
%K A385858 nonn
%O A385858 1,2
%A A385858 _Robert G. Wilson v_, Jul 10 2025