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 A038578 #15 Jul 08 2025 22:24:27
%S A038578 1,8,16,40,88,184,388,800,1628,3288,6584,13096,25904,50984,99916,
%T A038578 195072,379572,736360,1424672,2749672,5295240,10176856,19522644,
%U A038578 37387424,71487756,136492216,260255304,495618408,942731360,1791241544,3399976348
%N A038578 Number of self-avoiding closed walks from 0 of area n in strip Z X {-1,0,1}.
%D A038578 J. Labelle, Self-avoiding walks and polyominoes in strips, Bull. ICA, 23 (1998), 88-98.
%H A038578 <a href="/index/Rec#order_06">Index entries for linear recurrences with constant coefficients</a>, signature (2,1,0,-3,-2,-1).
%F A038578 G.f.: -3+4(1-x^2+x^4)/(1-x-x^2-x^3)^2 [Labelle]. - _Emeric Deutsch_, Apr 29 2004
%t A038578 LinearRecurrence[{2, 1, 0, -3, -2, -1}, {1, 8, 16, 40, 88, 184, 388}, 31] (* _Georg Fischer_, Jan 28 2021 *)
%o A038578 (PARI) Vec(-3+4*(1-x^2+x^4)/(1-x-x^2-x^3)^2 + O(x^40)) \\ _Michel Marcus_, Jan 28 2021
%Y A038578 Cf. A022444.
%K A038578 nonn,walk,easy
%O A038578 0,2
%A A038578 _N. J. A. Sloane_
%E A038578 More terms from _Emeric Deutsch_, Apr 29 2004