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 A001074 #13 Jul 29 2021 09:30:51 %S A001074 1,4,7,8,9,13,19,25,27,28,31,32,36,37,43,49,52,56,61,63,64,67,72,73, %T A001074 76,79,91,97,100,103,104,108,109,117,121,124,125,127,133,139,148,151, %U A001074 152,157,163,169,171,172,175,181,189,193,196,199,200,211,216,217 %N A001074 Numbers m such that Sum_{k=0..m-1} exp(2*Pi*i*k^3/m) != 0. %C A001074 Mark m points around a horizontal disk with labels 0..m-1; place coins at positions k^3 mod m for k=0..m-1; sequence gives values of m for which the disk is not balanced. %H A001074 T. D. Noe, <a href="/A001074/b001074.txt">Table of n, a(n) for n = 1..1000</a> %e A001074 8 is in the sequence because 4 coins go at 0, and 1 each at 1, 3, 5, 7, so the disk is unbalanced in the direction of point 0. %e A001074 12 is not in the sequence because there are 2 coins at 0, 4, 8 and 1 coin at 1, 3, 5, 7, 9, 11, so the disk is balanced. %t A001074 Select[Range[300], Sum[Exp[2 Pi*I*k^3/#], {k, 0, # - 1}] != 0 &] (* _T. D. Noe_, Jun 25 2012 *) %K A001074 nice,nonn,easy %O A001074 1,2 %A A001074 R. Lozyniak (11(AT)onna.com)