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 A258250 #54 Aug 16 2020 12:48:10 %S A258250 70,836,4030,5830,7192,7912,10792,17272,45356,83312,91388,113072, %T A258250 254012,388076,786208,1713592,4145216,4559552,4632896,9928792, %U A258250 11547352,13086016,15126992,17999992,29465852,29581424,34869056,37111168,38546576,74899952,89283592,95327216 %N A258250 Primitive weird numbers (pwn) (A002975) whose abundance (A033880) is a power of 2 (A000079). %C A258250 Number of terms < 10^n: 0, 1, 2, 6, 11, 15, 20, 32, 38, 48, 65, ..., . %C A258250 Of the total of 499 terms < 10^11 which are pwn, only about 13% have an abundance which are powers of two. %C A258250 Least term whose abundance has an exponent, e, of two > 1: 70, 836, 7192, 83312, 786208, 4145216, 98196134272, 4559552, 37111168, 22889716736, 141145802752, ?13?, 3307637248, ?15?, 154153326592, ..., . %C A258250 Least term which has k prime factors, not counting multiplicity > 2: 70, 4030, 29465852, 44257207676, ..., . %C A258250 Least term which has k prime factors, counting multiplicity > 2: 70, 836, 7192, 83312, 786208, 4145216, 37111168, 270788864, 2529837568, 22889716736, 141145802752, ..., . %H A258250 Robert G. Wilson v, <a href="/A258250/b258250.txt">Table of n, a(n) for n = 1..87</a> %H A258250 Mark Jaybee S. Biano, Bernadette S. Estoque, Lynden Aaron D. Galera, Maria Elena S. Rulloda, Daisy Ann A. Disu, <a href="http://docplayer.net/87034980-Vol-15-no-2-april-2017-dmmmsu-cas-science-monitor.html">On Weird Numbers</a>, DMMMSU-CAS Science Monitor (2016-2017) Vol. 15 No. 2, 157-162. %e A258250 70 is in the sequence since sigma(70) = 144 which yields an abundance of 4 = 2^2. %t A258250 (* copy the terms from A002975 and assign them to lst and then *) f[n_] := DivisorSigma[1, n] - 2n; lst[[#]] & /@ Select[ Range@ 695, IntegerQ@ Log2@ f@ lst[[#]] &] %Y A258250 Cf. A002975, A000079, A033880. %K A258250 nonn %O A258250 1,1 %A A258250 _Robert G. Wilson v_, Jun 19 2015 %E A258250 Corrected by _Robert G. Wilson v_, Dec 08 2015