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 A293187 #12 Jan 18 2020 03:14:04 %S A293187 480,840,1080,1320,1512,1560,1680,1848,1890,1920,2040,2184,2280,2376, %T A293187 2688,2760,2856,3000,3192,3240,3360,3480,3720,3840,4320,4440,4920, %U A293187 5160,5280,5640,5880,6048,6240,6360,6720,7080,7320,7392,7560,7680,8040,8160,8520 %N A293187 Bi-unitary 3-abundant numbers: numbers k such that bsigma(k) > 3*k, where bsigma is the sum of the bi-unitary divisors function (A188999). %C A293187 Analogous to 3-abundant numbers (A023197) with bi-unitary sigma (A188999) instead of sigma (A000203). %H A293187 Amiram Eldar, <a href="/A293187/b293187.txt">Table of n, a(n) for n = 1..10000</a> %e A293187 480 is in the sequence since bi-unitary sigma(480) = 1512 > 3 * 480. %t A293187 f[n_] := Select[Divisors[n], Function[d, CoprimeQ[d, n/d]]]; bsigma[m_] := DivisorSum[m, # &, Last@Intersection[f@#, f[m/#]] == 1 &]; bAbundantQ[n_] := bsigma[n] > 3 n; Select[Range[1000], bAbundantQ] (* after _Michael De Vlieger_ at A188999 *) %Y A293187 Cf. A023197, A285615, A188999, A292982. %K A293187 nonn %O A293187 1,1 %A A293187 _Amiram Eldar_, Oct 01 2017