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 A271465 #9 Nov 30 2016 01:02:47 %S A271465 1,1,1,1,2,1,1,3,4,1,1,4,11,8,1,1,5,28,38,16,1,1,6,69,178,126,32,1,1, %T A271465 7,168,844,1008,415,64,1,1,8,407,4012,8590,5493,1369,128,1,1,9,984, %U A271465 19072,74148,81445,29879,4521,256,1 %N A271465 Array read by antidiagonals: T(n,m) = number of self-avoiding walks of any length from NW to SW corners on a grid with n rows and m columns. %H A271465 Andrew Howroyd, <a href="/A271465/b271465.txt">Table of n, a(n) for n = 1..378</a> %F A271465 T(1,n)=1, T(2,n)=n, T(n,1)=1, T(n,2)=2^(n-1). %e A271465 The start of the sequence as table: %e A271465 * 1 1 1 1 1 1 1 ... %e A271465 * 1 2 3 4 5 6 7 ... %e A271465 * 1 4 11 28 69 168 407 ... %e A271465 * 1 8 38 178 844 4012 19072 ... %e A271465 * 1 16 126 1008 8590 74148 638472 ... %e A271465 * 1 32 415 5493 81445 1246850 19011465 ... %e A271465 * 1 64 1369 29879 761047 20477490 550254085 ... %e A271465 * ... %Y A271465 Main diagonal is A271507. Rows include A005409, A214931. Columns include A006189, A216211. Cf. A064298 (paths from NW to SE). %K A271465 nonn,tabl %O A271465 1,5 %A A271465 _Andrew Howroyd_, Apr 08 2016