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 A078528 #11 Jul 03 2025 20:39:08 %S A078528 1,1,2,5,15,30,76,170,422,961,2339,5390,12977,30059,71918,167019, %T A078528 397691,924931,2194478,5107991,12085695,28143758,66442935,154759821, %U A078528 364706675,849562628 %N A078528 Number of unconstrained walks on square lattice trapped after n steps. %C A078528 See under A078527. In the probability sum in A077483 and A078526 the unconstrained walks are responsible for the occurrence of 3^(n-1) in the denominator of P(n). %H A078528 Hugo Pfoertner, <a href="http://www.randomwalk.de/stw2d.html">Results for the 2D Self-Trapping Random Walk</a> %e A078528 a(7)=1 because the unique shortest walk contains no constrained steps. a(10)=5: See illustration in "5 Unconstrained and 7 maximally 2-constrained walks of length 10" given at link. %o A078528 (Fortran) c Program provided at given link %Y A078528 Cf. A077482, A077483, A078526, A078527, A001411. %K A078528 more,nonn %O A078528 7,3 %A A078528 _Hugo Pfoertner_, Nov 27 2002 %E A078528 a(24)-a(32) from _Sean A. Irvine_, Jul 03 2025