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 A175837 #15 Jul 22 2025 07:56:29
%S A175837 12,18,24,30,36,40,42,48,54,56,60,66,70,72,78,80,84,88,90,96,100,102,
%T A175837 108,112,114,120,126,132,138,140,144,150,156,160,162,168,174,176,180,
%U A175837 186,192,196,198,200,204,208,210,216,220,222,224,228,234,240,246,252
%N A175837 (2n-1)-abundant numbers.
%C A175837 A number k is (2n-1)-abundant if sum_{d|k, d<k} (2*d-1) > 2*k-1, a specialization of the definition in A175522.
%C A175837 Adding 2k-1 on both sides of the condition yields the equivalent condition A129246(k) > 2*(2k-1).
%C A175837 Adding 2k-1 on both sides also yields sum_{d|k} (2*d-1) > 2*(2k-1), equivalent to 2*sum_{d|k}d - tau(k) > 2*(2k-1) or sigma(k) > 2k-1+tau(k)/2, equivalent to A033880(k) > tau(k)/2-1.
%F A175837 A175837 = { n | A033880(n) > A000005(n)/2-1 }.
%t A175837 aQ[n_] := DivisorSum[n, 2#-1&, #<n&] > 2n-1; Select[Range[252], aQ] (* _Amiram Eldar_, Feb 18 2019 *)
%Y A175837 Cf. A175522, A033880, A000203, A005100, A005101.
%K A175837 nonn
%O A175837 1,1
%A A175837 _Vladimir Shevelev_, Dec 05 2010
%E A175837 More terms from _Amiram Eldar_, Feb 18 2019