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 A268487 #32 Mar 31 2016 13:42:17 %S A268487 11,13,19,21,25,26,31,33,35,43,47,49,52,53,54,55,59,61,65,66,71,73,74, %T A268487 76,79,81,83,84,85,86,87,89,91,93,95,96,97,98,99,103,107,108,109,114, %U A268487 115,116,117,118,119,120,121,123,125,128,129 %N A268487 Numbers of equal electric charges for which the minimum-potential dislocation on a sphere has nonzero sum of position vectors. %C A268487 Probably most of these terms are merely conjectural. - _N. J. A. Sloane_, Mar 31 2016 %C A268487 Given m identical point charges located on a sphere, their minimum-potential dislocation (the Thomson problem) may, but need not, have high enough symmetry for the sum of their position vectors Sum[i=1..m](r_i) to be zero. This sequence lists, in increasing order, the values of m for which the sum is nonzero. %C A268487 Numeric investigations were carried out by various authors for m = 1 to 204, and then for a number of selected cases (see references in the Wikipedia link). Among the studied cases, 312 is also known to belong to this sequence. All these cases have at most some type of C-symmetry (C_2,C_2v,C_s,C_3,C_3v). So far, 10 cases with no symmetry at all (C_1) were found, namely m = 61, 140, 149, 176, 179, 183, 186, 191, 194, 199. No simple algorithm to handle this open problem, nor a general formula, are known. %H A268487 Stanislav Sykora, <a href="/A268487/b268487.txt">Table of n, a(n) for n = 1..100</a> %H A268487 Steve Smale, <a href="http://link.springer.com/article/10.1007%2FBF03025291">Mathematical Problems for the Next Century</a>, Mathematical Intelligencer, 20 (1998), 7-15. %H A268487 Wikipedia, <a href="http://en.wikipedia.org/wiki/Thomson_problem">Thomson problem</a> %K A268487 nonn,hard %O A268487 1,1 %A A268487 _Stanislav Sykora_, Feb 08 2016