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 A033859 #15 Jul 02 2025 16:01:56 %S A033859 8,16,24,27,36,40,54,81,88,100,104,120,125,135,136,152,168,184,189, %T A033859 196,225,232,248,250,264,270,272,280,296,297,312,328,343,344,351,375, %U A033859 376,378,408,424,440,441,456,459,472,484,488,513,520,536,568,584,594,616 %N A033859 Numbers k such that A033831(k) = A034444(k) where A034444(k) = number of unitary divisors of k. %H A033859 Amiram Eldar, <a href="/A033859/b033859.txt">Table of n, a(n) for n = 1..10000</a> %p A033859 with(numtheory): for n from 1 to 1200 do it := divisors(n): count := 0: for i from 1 to nops(it) do if it[i]>=3 and 1<=n/it[i] and n/it[i]<=(it[i]-2) then count := count+1 fi:od: if count=2^nops(ifactors(n)[2]) then printf(`%d,`,n) fi; od: %t A033859 j[n_] := DivisorSum[n, 1&, # > 2 && n/# < #-1 &]; Select[Range[1000], j[#] == 2^PrimeNu[#] &] (* _Amiram Eldar_, Jun 11 2019 *) %Y A033859 Cf. A033831, A034444. %K A033859 easy,nonn %O A033859 1,1 %A A033859 _Naohiro Nomoto_ %E A033859 More terms from _James Sellers_, Jun 20 2000