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 A334898 #12 May 17 2020 02:15:28
%S A334898 1,2,6,8,24,30,32,40,42,48,54,56,66,72,78,88,96,104,120,128,160,168,
%T A334898 192,210,216,224,240,264,270,280,288,312,320,330,336,352,360,378,384,
%U A334898 390,408,416,432,440,448,456,462,480,486,504,510,512,520,528,544,546,552
%N A334898 Bi-unitary practical numbers: numbers m such that every number 1 <= k <= bsigma(m) is a sum of distinct bi-unitary divisors of m, where bsigma is A188999.
%C A334898 Includes 1 and all the odd powers of 2 (A004171). The other terms are a subset of bi-unitary abundant numbers (A292982) and bi-unitary pseudoperfect numbers (A292985).
%H A334898 Amiram Eldar, <a href="/A334898/b334898.txt">Table of n, a(n) for n = 1..2500</a>
%t A334898 biunitaryDivisorQ[div_, n_] := If[Mod[#2, #1] == 0, Last @ Apply[Intersection, Map[Select[Divisors[#], Function[d, CoprimeQ[d, #/d]]] &, {#1, #2/#1}]] == 1, False] & @@ {div, n}; bdivs[n_] := Module[{d = Divisors[n]}, Select[d, biunitaryDivisorQ[#, n] &]]; bPracQ[n_] := Module[{d = bdivs[n], sd, x}, sd = Plus @@ d; Min @ CoefficientList[Series[Product[1 + x^d[[i]], {i, Length[d]}], {x, 0, sd}], x] > 0]; Select[Range[1000], bPracQ]
%Y A334898 The bi-unitary version of A005153.
%Y A334898 Cf. A004171, A188999, A286652, A292982, A292985, A334901.
%K A334898 nonn
%O A334898 1,2
%A A334898 _Amiram Eldar_, May 16 2020