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 A306867 #17 Mar 16 2019 15:27:54
%S A306867 434784,1100176,1252216,1754536,2166136,2362360,3064096,6224890,
%T A306867 7626136,7851256,7950096,9026235,9581320,12494856,13324311,14192080,
%U A306867 15218560,15243424,15422536,19028296,19466560,19555360,29180466,36716680,37542190,40682824,44044000,44588896
%N A306867 Lesser of augmented bi-unitary amicable pair.
%C A306867 A pair m < n is an augmented bi-unitary amicable pair if bsigma(m) = bsigma(n) = m + n - 1, where bsigma(n) is the sum of bi-unitary divisors of n (A188999).
%C A306867 The larger members are in A306868.
%H A306867 Amiram Eldar, <a href="/A306867/b306867.txt">Table of n, a(n) for n = 1..509</a> (terms below 2*10^11, from David Moews's site).
%H A306867 David Moews, <a href="http://djm.cc/amicable.html">Perfect, amicable and sociable numbers</a>.
%e A306867 434784 is in the sequence since it is the lesser of the amicable pair (434784, 871585): bsigma(434784) = bsigma(871585) = 1306368 = 434784 + 871585 - 1.
%t A306867 fun[p_, e_]:=If[OddQ[e], (p^(e+1)-1)/(p-1), (p^(e+1)-1)/(p-1)-p^(e/2)]; bsigma[1] = 1; bsigma[n_] := Times @@ (fun @@@ FactorInteger[n]); f[n_] := bsigma[n] - n + 1; s={}; Do[m = f[n]; If[m > n && f[m] == n, AppendTo[s, n]], {n, 1, 10^7}]; s
%Y A306867 Cf. A007992, A126174, A188999, A292980, A306868.
%K A306867 nonn
%O A306867 1,1
%A A306867 _Amiram Eldar_, Mar 14 2019