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 A245213 #14 Sep 08 2022 08:46:08 %S A245213 72,96,120,144,180,192,216,240,288,336,360,384,432,480,504,528,540, %T A245213 576,600,624,648,672,720,756,768,792,840,864,900,936,960,972,1008, %U A245213 1056,1080,1120,1152,1176,1200,1224,1248,1260,1280,1296,1320,1344,1368,1440,1512 %N A245213 Numbers n such that A245212(n) < n. %C A245213 Numbers n such that A245212(n) = (n * tau(n)) - Sum_((d<n) | n) (d * tau(d)) < n. %C A245213 If d are divisors of n then values of sequence A245212(n) are the bending moments at point 0 of static forces of sizes tau(d) operating in places d on the cantilever as the nonnegative number axis of length n with support at point 0 by the schema: A245212(n) = (n * tau(n)) - Sum_((d<n) | n) (d * tau(d)). %H A245213 Jens Kruse Andersen, <a href="/A245213/b245213.txt">Table of n, a(n) for n = 1..10000</a> %e A245213 Number 72 is in sequence because A245212(72) = 62 < 72. %o A245213 (Magma) [n: n in [1..100000] | (2*(n*(#[d: d in Divisors(n)]))-(&+[d*#([e: e in Divisors(d)]): d in Divisors(n)])) lt n] %Y A245213 Cf. A000005, A100484, A245211, A245212, A245214. %K A245213 nonn %O A245213 1,1 %A A245213 _Jaroslav Krizek_, Jul 23 2014