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 A360715 #23 Mar 04 2023 20:36:52 %S A360715 1,3,9,30,105,369,1281,4380,14769,49215,162393,531450,1727193,5580141, %T A360715 17936145,57395640,182948577,581130747,1840247337,5811307350, %U A360715 18305618121,57531942633,180441092769,564859072980,1765184603025,5507375961399,17157594341241,53379182394930,165856745298489,514727830236645 %N A360715 Number of self-avoiding paths with nodes chosen among n given points on a circle; one-node paths are allowed. %H A360715 Ivaylo Kortezov, <a href="http://www.wfnmc.org/journal.html">Sets of Paths between Vertices of a Polygon</a>, Mathematics Competitions, Vol. 35 (2022), No. 2, ISSN:1031-7503, pp. 35-43. %H A360715 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (8,-22,24,-9). %F A360715 a(n) = (n/4)*(3^(n-1)+3). %e A360715 a(4) = A001792(2) + 4*A001792(1) + 6 + 4 = 8 + 4*3 + 6 + 4 = 30 with the four summands corresponding to paths with 4, 3, 2 and 1 nodes, respectively. %Y A360715 If one-node paths are not allowed, one gets A261064. Cf. A001792 if all n points need to be used. %K A360715 nonn,easy %O A360715 1,2 %A A360715 _Ivaylo Kortezov_, Feb 18 2023