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 A323857 #8 Feb 10 2019 23:07:47 %S A323857 1,14,135,1144,9083,69690,522781,3864524,28243251,204687550, %T A323857 1473038447,10542725976,75096139471,532846305962,3767808141891, %U A323857 26566180648012,186826646453453 %N A323857 Sum of end-to-end Manhattan distances over all self-avoiding n-step walks on 4-d cubic lattice. %C A323857 The first step is kept fixed, i.e., (0,0,0,0) -> (1,0,0,0). %e A323857 a(3) = 135, because there are 6 (of A010575(3)/8=49) end points with Manhattan distance 1, (0,-1,0,0), (0,1,0,0), (0,0,-1,0), (0,0,1,0), (0,0,0,-1), (0,0,0,1), and the remaining 43 end points all have Manhattan distance 3, e.g., (3,0,0,0), (2,-1,0,0), ..., (1,-1,-1,0), ... 135 = 6*1 + 43*3. %Y A323857 Cf. A010575, A079156, A242355, A323856. %K A323857 nonn,walk,more %O A323857 1,2 %A A323857 _Hugo Pfoertner_, Feb 03 2019