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 A198806 #23 Feb 06 2024 08:10:22
%S A198806 1,0,14,0,546,0,32900,10080,2570050,2540160,238935564,465696000,
%T A198806 25142196156,76886409600,2900343069624,12211317518400,359067702643650,
%U A198806 1915829643087360,47006105030584700,300455419743198720,6437718469449262996
%N A198806 Number of closed paths of length n whose steps are 14th roots of unity, U_14(n).
%C A198806 U_14(n), (comment in article): For each m >= 1, the sequence (U_m(N)), N >= 0 is P-recursive but is not algebraic when m > 2.
%H A198806 Andrew Howroyd, <a href="/A198806/b198806.txt">Table of n, a(n) for n = 0..200</a>
%H A198806 Gilbert Labelle and Annie Lacasse, <a href="https://doi.org/10.46298/dmtcs.2937">Closed paths whose steps are roots of unity</a>, in FPSAC 2011, Reykjavik, Iceland DMTCS proc. AO, 2011, 599-610.
%F A198806 E.g.f.: BesselI(0,2*x)^7 + 2*Sum_{k>=1} BesselI(k,2*x)^7. - _Andrew Howroyd_, Nov 01 2018
%o A198806 (PARI) seq(n)={Vec(serlaplace(sum(k=0, n, if(k,2,1)*(x^k*besseli(k, 2*x + O(x^(n-k+1)))/k!)^7)))} \\ _Andrew Howroyd_, Nov 01 2018
%Y A198806 Cf. A002898, A070190, A071549.
%K A198806 nonn
%O A198806 0,3
%A A198806 _Simon Plouffe_, Oct 30 2011