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 A033858 #9 Jul 14 2019 07:30:33 %S A033858 1,2,4,8,9,12,20,24,25,27,40,49,54,88,104,120,121,125,135,136,152,168, %T A033858 169,184,189,232,248,250,264,270,280,289,296,297,312,328,343,344,351, %U A033858 361,375,376,378,408,424,440,456,459,472,488,513,520,529,536,568,584 %N A033858 Numbers k such that j(k) + ud(k) = d(k), where j(k) = A033831, ud(k) = number of unitary divisors of k (A034444), d(k) = number of divisors of k (A000005). %H A033858 Amiram Eldar, <a href="/A033858/b033858.txt">Table of n, a(n) for n = 1..10000</a> %t A033858 j[n_] := DivisorSum[n, 1&, # > 2 && n/# < #-1 &]; Select[Range[10^3], j[#] + 2^PrimeNu[#] == DivisorSigma[0, #] &] (* _Amiram Eldar_, Jul 14 2019 *) %Y A033858 Cf. A000005, A033831, A034444. %K A033858 easy,nonn %O A033858 1,2 %A A033858 _Naohiro Nomoto_ %E A033858 More terms from _Amiram Eldar_, Jul 14 2019