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 A288688 #7 Jun 01 2025 19:54:59
%S A288688 1,1,5,31,201,1206,6751,36051,187025,954136,4822527,24251877,
%T A288688 121631329,609151986,3048441935,15249510871,76267672545,381394509228,
%U A288688 1907131201327,9536109476745,47681856564305,238413094649734,1192076649237855,5960416195898811
%N A288688 Number of n-digit biquanimous strings using digits {0,1,...,4}.
%C A288688 A biquanimous string is a string whose digits can be split into two groups with equal sums.
%H A288688 Alois P. Heinz, <a href="/A288688/b288688.txt">Table of n, a(n) for n = 0..1000</a>
%H A288688 <a href="/index/Rec#order_09">Index entries for linear recurrences with constant coefficients</a>, signature (18, -137, 582, -1527, 2574, -2795, 1890, -724, 120).
%F A288688 G.f.: -(60*x^10 -422*x^9 +1044*x^8 -1855*x^7 +2394*x^6 -2122*x^5 +1273*x^4 -504*x^3 +124*x^2 -17*x +1) / ((5*x-1) *(3*x-1) *(2*x-1)^3 *(x-1)^4).
%Y A288688 Column k=4 of A288638.
%K A288688 nonn,easy
%O A288688 0,3
%A A288688 _Alois P. Heinz_, Jun 13 2017